Electronic audio communications systems network

ABSTRACT

An advanced electronic telecommunications system is provided for the deposit, storage and delivery of audio messages to both user and non-users with limited access provided to the non-user under the control of the user. A Voice Message System (10) interconnects multiple private exchanges (12) of a subscriber with a central telephone office (22). Individual subscriber users may access the Voice Message System (10) through ON NET telephones (18) or OFF Net telephones (24). Selected non-users may be allowed access through the OFF NET telephones (24), the scope of the access of the selected non-users is determined by a subscriber user. The Voice Message System (10) includes an administrative subsystem (60), call processor subsystem (62) and a data storage subsystem (64). The Voice Message System (10) enables the user to deposit a message in data storage subsystem (64) for automatic delivery to other addresses connected to the system. Individual systems (42) can be linked in a network (40) by either a digital data link (48) or a public telephone network (51). The Voice Message System (10) also enables a user to access the system to determine if any messages have been in data storage subsystem (64) for him. Prerecorded instructional messages are deposited in the data storage subsystem (64) for instructing a user or a selected non-user on their progress in using the system.

RELATED APPLICATIONS

This is a continuation-in-part of parent application Ser. No. 97,240filed Nov. 26, 1979, now U.S. Pat. No. 4,371,752 issued Feb. 1, 1983.

TECHNICAL FIELD

This invention relates to telecommunication systems, and moreparticularly to an electronic digital signal processor controlledtelecommunication systems network.

BACKGROUND ART

In response to the problems encountered in improving the communicationsbetween people desiring rapid and efficient delivery of verbal messagesin the business community, electronic message systems that store audiomessages in a digital form have very recently been developed. Thesesystems allow a caller to store the digital form of his message forlater retrieval by the person he is directing the message to. Eventhough these systems greatly increase the efficiency of communicationbetween parties, the need for even more versatility in communicationability still exists. For example, these voice storage systems that areavailable to a select group of callers such as the employees of acorporation may have many different branches connected to differentsystems. In order to increase the versatility of a particular system, itis necessary that they be able to communicate with each other throughany means available. In order to accomplish this, the systems thatdesire to communicate with each other must coordinate their respectivefunctions such as receiving or transmitting information over a commontransmitting medium.

The simultaneous transmission and reception of voice information forintended recipients over a common transmitting medium can be a difficulttask to accomplish for a machine. This is due to the fact that a greatdeal of information traffic is present along a common data link. One ofthe most commonly used means of communicating between two computersystems in a highspeed digital data link that utilizes techniques suchas time sharing. These type of data links enable two computers toconverse with one another if the proper connections are made. However,these data links are not always available to a computer and, as such, itis not always efficient to utilize this type of data link fortransmitting digitized message data. Sometimes the data link is eitherbusy or not available for system use. Therefore, there exists a need forestablishing a communication link between two voice message systems withthe requisite versatility that does not require the sole use of adigital data link.

SUMMARY OF THE INVENTION

The present invention described and disclosed herein comprises anelectronic communication network enabling communication between remotelocations of a user's network telephone facility. The communicationnetwork includes a plurality of remotely-disclosed electroniccommunications systems that are coupled to remote portions of thetelephone facilities of a user's network telephone facility. Each of theelectronic communications systems includes a mechanism that isresponsive to signals transmitted to the user's telephone facility forenabling access to each of the systems. After the audio messages havebeen transmitted from the user's telephone facility, digitalrepresentations thereof are stored in a digital storing circuit. Thesemessages are accessed from the storage apparatus by an accessingmechanism which accesses the audio messages for a selected recipient inresponse to the route data. The audio messages are reproduced and atransmitter is provided for transmitting the audio messages to thetelephone station of the message recipient. A circuit is provided forconverting the representations of the route data to tone digit signalsand the reproduced audio messages over the user's telephone facility toa selected one of the communication systems. Each of the communicationssystems also includes an analog receiver for receiving the tone digitsignals and the reproduced audio messages from the user's telephonefacility that were transmitted there from another one of thecommunications systems. A circuit is provided for converting the tonedigit signals to digital representations of the route data.

In another embodiment of the present invention, the route data istransmitted over a digital data link by a digital transmitter and adigital receiver is operable to receive the digital representations ofthe route data transmitted over the data link. The audio messages aretransmitted synchronously with the route data over the user's telephonenetwork in an analog format for reception by the analog receiver.

In yet another embodiment of the present invention, a method forenabling communications between remote locations of a user's networktelephone facility is provided that includes the steps of accessing oneof the plurality of remotely-disposed electronic systems andtransmitting analog data from the user's telephone facility to one ofthe electronic communications systems. The analog data is processed byreceiving the analog data transmitted from the telephone user'sfacility, discriminating the analog data into audio message data andassociated data, the associated data comprising route data indicatingthe originator of the audio message. The message data is then stored asdigital representations along with the associated data and then theaudio message data is reproduced from the stored digital representationsof the audio message data for transmission to the intended recipient.The digital representations of the associated data is also converted totone digit signals and transmitted along with the reproduced audiomessages over the user's telephone facility to a selected one of thecommunication systems. Tone digit signals of route data and reproducedaudio messages are received from another one of the communicationsystems in the network, and the tone digit signals are converted todigital representations of the associated data.

In a further embodiment of the present invention, the digitalrepresentations of the associated data are transmitted over a digitaldata link to another one of the communication systems sychronously withreproduced audio message data. The audio message data and the digitallytransmitted associated data are then received sychronously. Otheraspects and advantages of the present invention become apparenthereinafter.

BRIEF DESCRIPTION OF DRAWINGS

Other objects and advantages of the present invention will be apparentfrom the following Detailed Description of the preferred embodimentsthereof and from the attached Drawings of which:

FIG. 1 illustrates a Voice Message System connected with the multipleprivate exchanges of a customer and the central office of the telephonecompany;

FIG. 2 illustrates a network of Voice Message Systems;

FIG. 3 is a block diagram of the Voice Message System of FIGS. 1 and 2;

FIG. 4 is a block diagram view of the call processor subsystem of theVoice Message System of FIG. 3;

FIG. 5 is a block diagram view of the communication port interface, portdriver modules and Codecs connecting the telephone handsets (of the callprocessor subsystem of FIG. 4);

FIG. 6 is a block diagram view of the administrative subsystem for theVoice Message System of FIG. 3;

FIG. 7 is a block diagram view of the storage subsystem of the VoiceMessage System of FIG. 3;

FIG. 8 is a block diagram view of the port driver subsystem of thecommunication port interface of FIG. 5;

FIG. 9 is a block diagram view of the Codec of the port driver subsystemof FIG. 8;

FIGS. 10a to 10n and 10j' are the schematic drawings of the UniversalControl Board programmable to function as the communication portinterface disk adapters and block transfer bus interface of the callprocessor subsystem of FIG. 4, the expander of the communication portinterface subsystem of FIG. 5 and the disk adapters and block transferbus interface of the administrative subsystem of FIG. 6.

FIG. 11 is a flow chart of the message deposit function of the voicemessage system;

FIG. 12 is the flow chart of the process user-I.D. subroutine of themessage deposit function of the voice message system;

FIG. 13 is the flow chart of the process and addressee subroutine of themessage deposit function of the voice message system;

FIG. 14 is a flow chart of the record voice message subroutine of themessage deposit function of the voice message system;

FIG. 15 is a flow chart of the message delivery function of the voicemessage system;

FIG. 16 is a flow chart of the process user I.D. subroutine of themessage delivery function of the voice message system;

FIG. 17 is a flow chart of the play voice message subroutine of themessage delivery function of the voice message system;

FIG. 18 is a flow chart of the redirect special function code subroutineof the message delivery function of the voice message system;

FIG. 19 is a flow chart of the reply special function code of themessage delivery function of the voice message system;

FIG. 20 is a flow chart of the save special function code subroutine ofthe message delivery function of the voice message system;

FIG. 21 is a flow chart of the inquiry function of the voice messagesystem;

FIG. 22 is a visual Table of Contents of all the programs in the VMSsystem software;

FIG. 23 illustrates the control and data flow for the programs runningin the call processors;

FIG. 24 illustrates the control and data flow for the programs residingin the master and slave processors of the administrative subsystem;

FIGS. 25a to 25c are the schematic drawings of the Codec of FIG. 9;

FIGS. 26a to 26h are the schematic drawings of the port driver subsystemof FIG. 8;

FIGS. 27a and 27b illustrate a flow chart of an alternate embodiment ofthe message delivery function;

FIG. 28 is a flow chart of the message receipt subroutine in the flowchart of FIGS. 27a and 27b;

FIGS. 29a and 29b illustrate a flow chart of the send message subroutinein the flow chart of FIGS. 27a and 27b;

FIG. 30 is a flow chart of the redirect feature;

FIG. 31 is a flow chart of the user changeable group codes feature;

FIG. 32 is a flow chart of the automatic variable time scan feature;

FIG. 33 is a flow chart of the quiet time compression feature;

FIG. 34 is a flow chart of the edit feature;

FIG. 35 is a flow chart of the DID/ICH feature;

FIG. 36 is a flow chart of the RO message address recording feature;

FIG. 37 is a flow chart for the RO message address access feature;

FIG. 38 is a flow chart for the personal information message feature;

FIG. 39 is a flow chart for the interactive voice message systemfeature;

FIG. 40 is a flow chart of an alternate embodiment of the messagedelivery feature;

FIG. 41 is a flow chart of the sequential group calling feature;

FIG. 42 is a flow chart of the status check feature;

FIG. 43 is a flow chart of the DID answer delay feature;

FIG. 44 is a flow chart of the FAX transmission feature;

FIG. 45 is a flow chart of the analog networking feature; and

FIG. 46 is a flow chart of the hybrid networking feature.

DESCRIPTION OF PREFERRED EMBODIMENT

Referring to FIG. 1, a Voice Message System advanced verbalcommunication system (hereinafter "VMS") of the present invention isgenerally identified by the reference numeral 10. ("Voice MessageSystem" is a trademark of Electronic Communication Systems, Inc.) TheVMS system 10 is illustrated connected with a user's telephonecommunications network. The VMS system 10 is not limited to theparticular telephone communications network illustrated in FIG. 1, asthe present invention is capable of providing an improved communicationsnetwork for a variety of user's telephone systems.

The telephone communications network illustrated in FIG. 1 includesmultiple Private Branch Exchanges 12 (hereinafter "PBX 12")interconnected by tie lines 14 through Voice Connecting Arrangements(hereinafter "VCA") 16 to the VMS 10. The VMS 10 can also be connectedto a PBX 12 with station lines. The VCA unit is supplied by thetelephone company pursuant to Federal Communication Commission's tariffregulation to provide a line of demarcation between a private user'sequipment and the telephone company's equipment. In addition torepresenting what are referred to as Private Branch Exchanges the term"PBX" also includes but is not limited to PABX (Private Automatic BranchExchange), EPABX (Electronic Private Automatic Branch Exchange) and CBX(Computerized Branch Exchange), in addition to various off premisesswitching systems.

The user's telephones 18 connected to the PBX's 12 have access to theVMS 10 and are generally referred to as being on the network or "ONNET". The features of the VMS 10 may be utilized by a small customerwith a single PBX 12 or by much larger customers having multiple PBX's12 interfaced with a single VMS 10. Of course, the PBX's 12 of a largecorporate customer may be separated and located in distant physicalfacilities. Remotely located PBX's 12 may be interconnected to a centralVMS 10 by other means than the tie lines 14, e.g., they could beconnected by a microwave relay system.

The user's PBX's 12 are also connected through telephone lines 20 to acentral office 22, of the telephone company. In addition, the centraloffice 22 is interconnected through tie lines 14 and VCA 16 to the VMS10. The VMS 10 can also be connected to the central office 22 throughcentral office trunks. Telephones 24 outside the customer's owntelephone communications network or "OFF NET" allow a user access to theimproved communication capabilities provided by the VMS 10.

Referring to FIG. 2, a first VMS 10 is interconnected to a user'stelephone communications network as illustrated in FIG. 1 and describedabove. The first VMS 10 is interconnected to a second VMS 10 to form anetwork of VMS systems 40. The first VMS 10 interconnected with itsuser's telephone communication equipment comprises a first node 42 ofnetwork 40, while the second VMS 10 with its user's telephonecommunication equipment comprises the second node 44 of network 40. Thefirst VMS 10 is interconnected through a MODEM 46 for modulating thecommunications information from the first node 42 for transmission viathe transmissions link 48 to a MODEM 50. The MODEM 50 demodulates theinformation for use by the second VMS 10 of the second node 44. Thetransmission link 48 could comprise a microwave relay system forconnecting nodes 42 and 44 of the VMS network 40. Such a transmissionlink 48 could be transmitted through a satellite communications systemto provide an interconnection between distant VMS systems 10. The VMSsystems are also interconnected through a public telephone network 51for transmission of the data in analog format. Of course, the number andarrangement of interconnected VMS systems 10 are not limited to thearrangement of VMS network 40 of FIG. 2.

Referring to FIG. 3, the VMS 10 of FIG. 1 includes the followingsubsystems: an administrative subsystem 60, call processor subsystems62A-62C, and a data storage subsystem 64. There is only oneadministrative system 60 and data storage subsystem 64 for each VMSsystem 10, but there may be multiple call processor subsystems 62A-62C.The number of call processor subsystems 62A-62C required is a functionof the number of telephone lines interfacing with the VMS 10. Thus, aVMS 10 may have one call processor subsystem 62A or any number of suchsubsystems. While there is one data storage subsystem 64 for the VMS 10,the size of the data storage subsystem 64 may vary, depending upon thenumber of disk files required for operation of the VMS 10. The datastorage subsystem 64 functions as the storage medium for audio messagesin the system. A message deposited from a caller is stored in the VMSsystem 10, and the message is later delivered to the addressee.Instructional messages are also stored in the data storage subsystem 64to guide the user in using the VMS 10.

A block transfer bus 66 allows each call processor subsystem 62A-62C tobe connected to the administrative subsystem 60, as well as allowingeach of the call processor subsystems 62A-62C to communicate with oneanother.

Data storage buses 68A-68B connect the administrative subsystem 60, thecall processor subsystem 62A-62C and the data storage subsystem 64. Theadministrative subsystem 60 and each of the call processor subsystems62A-62C have access to each of the data storage buses 68A-68B. The twodata storage buses 68A-68B serve two functions. First, it providesredundancy in the VMS system 10, so that, if data storage bus 68Amisfunctions, data storage bus 68B allows the VMS 10 to continue tooperate. Secondly, when both of the data storage buses 68A-68B arefunctioning, it doubles the bandwidth of the data to be transmittedbetween the data storage system 64 and the call processor subsystems62A-C and administrative subsystem 60.

Referring to FIG. 4, the call processor subsystem 62A is illustrated inblock diagram form. A single board computer 70 contains amicroprocessor, some memory storage, and some input/output deviceinterfaces. The single board computer 70 may be implemented by Intel'ssingle board computer, from Intel, Model Number 80/30. The Intel 80/30computer includes an 8085 microprocessor, a 16K RAM, 8K ROM, as well assome input/output device interfaces.

A call processor memory 72 provides memory for the call processorsubsystem 62A and may be implemented by one or more individual boardscontaining RAM memory. A single board providing 64K bytes of RAM memorymay be utilized as the call processor memory unit 72 and is commerciallyavailable from Intel as Model No. SVC064. A communications portinterface 74 provides access to the communication port modules 90 ofFIG. 5 described hereinbelow. Two identical disk adapters 76 and 78interconnect with the data storage subsystem 64 of FIG. 3 through datastorages buses 68A and 68B. Finally, a block transfer bus interface 80is a hardware device required to interconnect with the block transferbus 66 of FIG. 3.

The communication port interface 74, disk adapters 76 and 78, and theblock transfer bus interface 80 are all implemented with an identicalelectronic unit, identified as a Universal Control Board. A UniversalControl Board contains as an Intel 8085 microprocessor, a RAM memorydevice, (approximately 500 bytes), a ROM memory device (approximately2K-4K bytes), and a digital data bus interface. A Universal ControlBoard's function is determined by the program controlling themicroprocessor. The schematic of a Universal Control Board isillustrated in FIGS. 10a-10m and described hereinbelow.

In addition to the memory provided in each of the Universal ControlBoards, the communication port interface 74, disk adapters 76 and 78 andblock transfer bus interface 80 all have access to the memory 72 of thecall processor subsystem 62A. Thus, the microprocessors of theseUniversal Control Boards communicate with the single board computer 70through the shared memory unit 72.

Referring now to FIG. 5, the communication port interface 74 of FIG. 4interfaces with the communication port driver modules 90A-B through acommunications port digital data bus 88. The communication port drivermodules 90A-90B are identical with one another, and each port drivermodule 90A-B may include a maximum of 16 identical port drivers 92. Anexpander 94 is a device for expanding the communications port data bus88 to the 16 port drivers 92 of each module 90A-B. The expanders 94 arealso implemented by a universal control board, illustrated in FIGS.10a-10m and described hereinbelow. Each port driver 92 is directlyconnected to a CODEC 96. The CODEC 96 is an abbreviated term for acircuit that functions as a coder/decoder. The CODEC 96 transforms theanalog voice signal to a digital bit stream for processing in the VMS10. The translated digital bit stream is fed up into the port driver 92for distribution to the remainder of the VMS system 10. In addition, intransmitting a recorded message outbound from the VMS 10 to the user,the outbound digital bit stream comes from the port driver 92 into theCODEC 96 where it is translated back into an analog voice signal whichis fed into the receiver of the telephone 18 of the user. A singlecommunication port interface 74 can drive up to 32 port drivers 92,which is equivalent to 32 telephone circuits to the VMS 10.

As required by the FCC tariff regulations, the CODEC 96 interfacesthrough a voice connecting arrangement 98 with the telephone 18 of theuser.

FIG. 6 illustrates the hardware implementing the administrativesubsystem 60 of FIG. 3. The hardware implementing the administrativesubsystem 60 is very similar to that implementing the call processorsubsystem 62A illustrated in FIG. 4 and described above.

A single board computer 100 (hereinafter "SBC 100") operates as thecentral processing unit for the administrative subsystem 60, and it isimplemented by a programmable single board computer, commerciallyavailable from Intel, Model No. 80/30. The SBC 100 has one input/outputinterface 102 connected to a cathode ray terminal 104, which serves asthe operator's console for the VMS 10. The second input/output interface106 of the SBC 100 drives a line printer 108. The line printer 108functions to produce reports and status information concerning theoperation of the VMS 10, and it also displays alarms for abnormalconditions during the system operation. One such alarm condition wouldresult from the failure of a recorded message to be transmitted from theVMS 10 in a predetermined period of time.

A memory unit 110 comprised of printed circuit boards provides thememory for the administrative subsystem 60. The memory unit 110 may bemade up of one or more individual printed circuit boards, each having64K bytes of RAM. These printed circuit boards are commerciallyavailable from Intel, Model SBC064. A nonvolatile memory unit 112provides memory for the administrative subsystem 60 so that the datastored in memory is not destroyed if the system loses power. The memoryunit 112 could also be implemented with core memory having a capacity of8 to 16K bytes.

Two identical disk adapters 114 and 116 interconnect through the datastorage buses 68A-68B to the data storage subsystem 64 of FIG. 3. Thedisk adapters 114 and 116 are implemented with a Universal Control Boardhaving its microprocessor programmed for the unit to run as a diskadapter. Finally, a block transfer bus interface 118 is connected to theblock transfer bus 66 to the call processor subsystem 62A of FIG. 3. Theblock transfer bus interface 118 is also implemented with a UniversalControl Board having a microprocessor programmed to control the unit'soperation.

FIG. 7 is a block diagram view of the storage subsystem 64 of the VMS 10of FIG. 3. FIG. 7 illustrates two identical disk storage units 120 withtheir associated disk controller 122. Each disk controller 122interfaces with the remainder of the system through disk ports 124A and124B through the data storage buses 68A and 68B. While FIG. 7illustrates two identical disk storage units 120 with their associateddisk controllers 122, the data storage subsystem 64 consists of anynumber of such identical units. The configuration of the VMS subsystem10 of FIG. 3 requires a minimum of two disk storage units 120, butadditional units may be added to increase the storage capacity of thesystem.

The entire disk storage unit 120 may be implemented by using a StorageTechnology Corporation disk drive, Model Number 2700. The STC Model 2700disk storage unit 120 is a rotating magnetic disk having a capacity for200 million 8 bit bytes of digital or binary information. Each disk unitcontains its own dedicated disk controller 122 which is built around amicroprocessor. The disk controller 122 may be implemented with aMotorola microprocessor, Model Number 6801, 64K bytes of RAM memory, andit also includes a special purpose digital hardware to drive theinput/output disk ports 124A and 124B into the disk unit 120 and todirectly control the disk storage unit 120. As additional disk storageunits 120 are added to the system, their associated disk ports 124A and124B are connected to the data storage buses 68A and 68B.

The VMS system 10 is provided with a minimum of two disk storage units120, since the functioning of the disk storage units 120 is essential tothe entire VMS system. The two data storage buses 68A and 68B areprovided to achieve redundancy in the system. If one of the buses goesout of service, then the other bus still has access to all of the diskunits 120 through the single remaining bus. With a single data bus inoperation, the system will still operate, but it will not have the samethroughput capability in terms of the amount of data that can beprocessed by the VMS 10. However, when both disk storage buses 68A and68B are running at normal operation, this allows twice as muchinformation to be fed into and out of the storage system 64 than couldbe accomplished with a single data storage bus.

A separate disk controller 122 dedicated to the operation of each diskstorage unit 120, enables blocks of information to be more efficientlytransferred within the VMS 10. For example, in transferring a block ofinformation from the call processor subsystem 62A or the administrativesubsystem 60 to or from the disk storage unit 120, the transfer does notoccur in real time from one of the data storage buses 68A or 68B ontothe disk unit 120. The block of information is transferred into the RAMstorage of the disk controller 122, and then the disk controller 122controls the operation of transferring the block of information from itsRAM directly into the disk unit 120. In this way, the VMS 10 storage bus68A or 68B is not tied up for the period of time it takes to write ablock of information directly onto the disk 120; rather, it is occupiedonly for the period of time it takes to transfer that block ofinformation into the RAM of the disk controller 122.

FIG. 8 is a block diagram view of one of the port drivers 92 of FIG. 5.The central control unit of the port driver 92 is an Intel 8085microprocessor 130 connected by an internal bus 132 to the remainder ofthe port driver system 92. The microprocessor 130 is programmed tocontrol a digital logic hardware device, identified as a bus interfacelogic unit 134. The bus interface logic 134 is an 8 or 16 bit wideparallel data path serving as the electrical interface between theexpander 94 in all of the port drivers 92. The bus interface logic 134consists of a bus backpane into which are plugged the boards for theport drivers 92 and expanders 94.

Voice data buffers 136 and 138 are connected to the remaining componentsof the port driver 92 through the internal bus 132. The voice databuffers 136 and 138 function to temporarily store the incoming oroutgoing data bit streams of the digitized voice signal incoming oroutgoing to the CODEC 96. The voice data buffers 136 and 138 interfacethrough a CODEC interface logic unit 140 to the CODEC 96. A ROM memoryunit 142 stores the program for the microprocessor 130.

The operation of the dual voice data buffers 136 and 138 may beillustrated by the example of digitized voice data being received by theport driver 92 from the CODEC 96. The voice data entering the portdriver 92 is temporarily stored in one of the dual voice data buffers136 or 138. When the selected voice data buffer is full, that entireblock of data is transmitted out to the expander 94 up to thecommunication port interface 74 of the call processor 62A. At the sametime when the port driver 92 senses that the first voice data buffer isfull, the second voice data buffer is used to store the subsequent voicedata from the CODEC 96. The port driver system 92 is programmed tocontrol the dual voice data buffers 136 and 138 in the transmitting modeand the storing mode. The voice data buffers 136 and 138 are implementedin RAM semiconductor memory in the range of 512-2K bytes.

FIG. 9 is a block diagram of the CODEC 96 of FIG. 5. A delta modulator150 (hereinafter "DM 150") is connected to the port driver 92. The DM150 functions as either a coder for converting analog signals to digitalsignals, or a decoder for converting digital signals to analog signals.The operating mode of the DM 150, whether it is functioning as a coderor decoder, is controlled by one of the interface signals 152 to theport driver 92. The DM 150 implements a particular technique forconverting analog to digital and digital to analog.

The DM 150 decodes the digital wave form to an analog signal and passesit through filter 154 which is a voice band filter with a cutofffrequency of approximately 2700 hertz. The analog signal from the filter154 is fed into a VCA interface logic 156, through a VCA 158 to the ONNET telephone 18. The VCA 158 is required by FCC Tariff Regulations asthe line of demarcation between the equipment of the telephone companyand the equipment of a private user.

The analog signal from the telephone 18 is transmitted through the VCA158 and VCA interface logic 156 to an automatic gain control circuit160, which serves to amplify the analog voice signal from the VCA. Theamplified analog signal is then passed through another band pass filter162 for passing frequencies in the range of approximately 300 hertz to2700 hertz. The filtered analog signal is then fed into the DM 150,which is functioning as a coder, and transformed into a digital bitstream to be fed to the port driver 92.

The first function of the CODEC 96 has been described above in providingthe data path for the incoming and outgoing voice signals from thetelephone 18 to the VMS system 10. An ancillary function of the CODEC 96is provided by a tone receiver 164, which receives the analog wave formsgenerated by the signal from a TouchTone type of telephone 18 andconverts these waveforms to digital information corresponding to thetone received. A tone generator circuit 166 provides the analogousfunction in converting digital signals from the VMS 10 to the receiverof the user telephone 18. The tone generator 166 functions to generateTouchTones as well as progress tone acknowledging the status of theoperation of the VMS 10. The tone generator 166 functions to form theoutgoing dialing in a TouchTone system. A pulse dialing path 168 isprovided to receive pulse dialing coming in from a rotary telephone 18,and it also functions to do the outbound dialing to a rotary telephone18.

FIGS. 10a-10m illustrate the Universal Control Board which isprogrammable to serve a number of functions in the VMS 10 describedabove. Universal Control Boards are utilized in the call processorsubsystem 62A illustrated in FIG. 4 to function as the communicationport interface 74, the disk adapters 76 and 78 and the block transferinterface bus 80. In addition, the expander 94 illustrated in FIG. 5 isimplemented with a Universal Control Board. In the administrativesubsystem 60, Universal Control Boards are programmed to function as thedisk adapters 114 and 116 as well as the block transfer interface bus118. The storage subsystem 64 illustrated in FIG. 7 utilizes a UniversalControl Board to function as the disk controllers 122.

The hardware for implementing the Universal Control Boards isillustrated in FIGS. 10a-10m and described hereinbelow. The hardware ofthe Universal Control Board is identical for each of the above-describedapplications in the VMS 10. The programs stored in the ROM of eachUniversal Control Board determines its function. For instance, thecommunication port interface 74, disk adapters 76 and 78 and blocktransfer bus interface 80 of the call processor subsystem 62A compriseindividual Universal Control Boards with identical hardware. Thesoftware program stored in the ROM determines whether the particularUniversal Control Board functions as a communication port interface 74or disk adapters 76-78 or the block transfer interface bus 80.

FIGS. 10a, 10b and 10c illustrate the basic microprocessor section ofthe board and includes a microprocessor 200 and memory input/outputcombination chips 202 and 204. The chips 202 and 204 have random accessmemory and I/O port features, while another combination chip 206 has aread only memory (ROM) in conjunction with I/O ports. Microprocessor 200is available commercially from Intel as Model No. 8085; the combinationchips 202 and 204 with RAM memory are commercially available from IntelModel No. 8155; and the ROM combination chip 206 is available from Intelas Model No. 8755.

A crystal 208 is the source of the clock signal for the microprocessor200, determining how fast it will run and how much time is allotted forexecution of an instruction.

As shown in FIG. 10c, reset circuitry 210 controls the start-up of themicroprocessor 200 when it is turned on and provides the means forresetting microprocessor 200. There are three different ways in whichthe microprocessor 200 may be restarted. First, the "power on" resetsignal comes into one pin of a reset OR gate 212 and goes through aninverter 214 to the microprocessor 200. The "power on" reset signaloriginates when system power is turned on and a resistor 216 slowlycharges a capacitor 218. Manual reset switch 220 is provided to manuallyreset the system by generating a grounded signal through an invertor 222and an invertor 224 to the input of the OR gate 212 to cause a reset anytime it is desired by the operator. The second method of restarting themicroprocessor 200 is from the IORST signal originating from anotherUniversal Control Board connected to the same bus to provide a resetsignal to reset OR gate 212. The third way to reset the microprocessor200 is through the general system reset signal passing through inverters222 and 224 to one pin of the reset OR gate 212. This signal is ageneral system reset and typically means that the reset occurred becauseeverything in the system has been reset. This general system resetsignal may be originated from another push button located elsewhere inthe system, like reset switch 220, which individually resets thisparticular microprocessor 200.

The reset signal from the OR gate 212 is fed separately throughinverters 226 and 228 to become reset signals "RST1" and "RST2" toprovide logic resets to other logic on the Universal Control Board otherthan the microprocessor 200.

As shown in FIG. 10j, an extended memory unit 170 is provided as anextension to the memory of the microprocessor 200. The extended memory170 comprises four functional units: (1) an address latch 172, (2) EPROMmemory units 174, 175, 176, 177, and 178, (3) RAM memory units, 180,181, 182, 183, 184, and 186, and (4) address decoding chips 187, 188,189, 190, 191, 192 and 193.

The address latch 172 is conditioned by the control signal ALE tocapture the address information (AD0-AD7) on an address data bus 230.The latched address is stored in address latch 172, which feeds itsoutput to all the EPROM chips 174-178 as well as all the RAM chips180-186.

The address decoding chips 187-193 decode the high order address signalsA10, A11, A12, A13, as well as the control signals RD and WR. Thesesignals are used to generate the output signals RAM1, RAM2 and RAM3.These signals control the activation of the individual EPROM chips174-178 and RAM chips 179-186.

The EPROM memory units 174-178 contain the stored program of theUniversal Control Board's 8085 processor. The combination of the addresslatch signals and the individual address decode signals control whichEPROM chip and which byte in the EPROM chip, is selected. The EPROMchips apply the selective data to the bus 230.

The RAM memory units 179-186 contain variable bytes of data which areused by the Universal Control Board's 8085 processor. The RAM memorychips 179-186 are selected by the address decode signals RAM1, RAM2, andRAM3. The RAM memory units 179-186 are selected in pairs, each chip inthe pair asserts four bits on the address data bus 230. Signals from theaddress latch 172 control which byte in the selected RAM chip isasserted on address data bus 230. The RAM chips 179-186 also use thesignal WR to store data in the RAM chip from the address data bus 230.

As shown in FIGS. 10a, 10b and 10d an address data bus 230 is abidirectional bus operating in a time multiplexed fashion. Part of thetime the bus 230 represents an address memory that needs to be involvedin a particular instruction, and at other times the bus 230 representsdata that is involved in a particular transaction and an instruction.This means the data can be going into or out of memory or into or out ofan input/output port. The address data bus 230 connects the signalsAD0-AD7 to one side of the bus repeater 232 for regenerating the databus. The data signals D0-D7 are connected through a data bus 234 to amemory address register 236 and a word count register 238. A control bus240 interconnects the various controls and timing signals from themicroprocessor 200 to the rest of the components in the combinationchips 202, 204 and 206 to instruct these devices in handling the signalson the address data bus 230.

The ALE signal originating in microprocessor 200 is the address latchused to tell the other components when the address data bus has anaddress on it. The other chips, 202, 204 and 206, have internal addressregisters which use the strobe to latch whatever information is on theaddress data bus 230 to save the address.

The IOM signal originates with the microprocessor 200 to tell the othercomponents connected to the microprocessor 200 that the particular datatransaction is either input/output or memory. The state of the signaltells the combination chips 202, 204 and 206, having input/outputfunctions and memory functions, that the data on the data lines andaddress on the address lines should be used to control either theinput/output ports or the memory ports. If the IOM signal is high, thisrepresents an input/output transaction; and if the signal is low itrepresents a memory transaction, either a read or write transaction.

The next strobe signal of the microprocessor 200 is the RD read signalwhich is a timing signal to tell the other components that themicroprocessor 200 is to perform a read function.

The next strobe signal is the WR write strobe originating with themicroprocessor 200 to tell the other system components that themicroprocessor 200 is to perform a write transaction, i.e., that it'sgoing to originate in the microprocessor and end up in an externalcomponent.

The next control signal is the RESET signal originating in themicroprocessor 200 which initializes the other combination chips 202,204 and 206.

The final control signal on the control bus 240 is the CLK signal, whichis a timing signal to the other combination chips 202, 204, and 206 sothat the whole system is synchronized.

The remaining signals, A8-A15, originating from the microprocessor 200to the ROM combination chip 206 to select which system component is tobe involved in a particular input/output or memory transaction. As shownin FIG. 10a, address signals A11-A13, connected to an address decoder244, may further select one of the chips 202, 204 and 206 in the systemto be involved in a transaction through its output signals DC0, DC1, andDC2. In addition, address decoder 244 also enables the microprocessor200 to select the desired ROM by outputting one of ROM1, ROM2, ROM3,ROM4, and ROM5 signals. As shown in FIG. 10d, the address signalsA13-A15 are connected to an input/output decoder 246 to decode theseaddresses into five unique signals to select certain registers tocontrol the memory address register 236 and the word count register 238of FIG. 10e. Of the five decoding signals provided by the input/outputdecoder 246, three of them, LDM0, LDM1 and LDM2, are used by the memoryaddress register 236. The remaining two decode signals of theinput/output decoder 246, LDM3 and LDM4, are used by the word countregister 238.

The memory address register 236 consists of address memory registers248, 250, 252, 254, and 256. The function of the memory address register236 is to address memory which is exterior to the Universal ControlBoard and connected to the Intel bus. The Intel bus is the main buswhich connects all the Universal Control Boards to one system. Thememory address register 238 can be loaded through input/output commandsto an initial starting address, which allows another controller in theboard to command it, incrementing its value through the INCDMA signalcoming into one pin of an AND gate 258. The INCDMA signal comes from abus timing control circuit 540 (FIG. 10m) on the Univeral Control Board.The other signal to the AND gate 258, MARINH, originates from a ROMsequencer 290 (FIG. 10f) on the Univeral Control Board and describedbelow.

The output of the memory address register 236 is transmitted to addressdrivers 260, which consist of separate drivers 262, 264, 266, 268, and270 connected to the memory address registers 248, 250, 252, 254, and256, respectively. The address drivers 260 take the memory address bitsindividually from the address registers 248-256 and condition them to beplaced on the Intel bus.

As shown in FIG. 10e, the word count register 238 consists of registers272, 274, 276, and 278 having their inputs connected to the data bus bar234 for receiving the data signals D0-D7. The word count register 238may have a starting count loaded into its registers through aninput/output command from the microprocessor 200. The word countregister 238 is controlled by the INCDMA signal for generating an outputsignal, word count zero (WCZERO) signal, to control how may bustransactions occur. For protocol on the Universal Control Board, theWCZERO signal is passed through an inverter 280 to output the signal asWCZERO.

As shown in FIG. 10f, a ROM sequencer 290 functions to control most ofthe logic on the Universal Control Board under the command of themicroprocessor 200. The ROM sequencer 290 controls bus transactions andcontrols transactions with whatever other device is connected to theUniversal Control Board on the other side of its cable.

The ROM sequencer 290 includes very high-speed memories in the form ofinterconnected PROMS 292, 294, 296 and 298. The input to the PROMS292-298 is its address and its output is program instruction for othercomponents of the Universal Control Board. The first four bitscomprising the output of the PROM 292 is the next address of the ROMprogram, and it is stored in the next address register 300. The PROM 294has as its output the four signals LOCKOK, MARINH, WRTINH, and MUXCON,which are applied elsewhere to the Universal Control Board. The PROM 296has three bits of its program output to control an output latch 302,which is a way for the program to express what it would like to do interms of output. The output latch 302 implements three signals: "STOP","BUSREQ" AND "RDONE". The output latch 302 is controlled by AND gate304, having its input terminals connected to a 5 megahertz clock signaland a pullup signal. The fourth bit from the PROM 296 occurs in realtime and is the DMA START signal, which is applied to a bus timingcontrol circuit 540 of FIG. 10m. Finally, the last PROM 298 has three ofits four bits of the program instruction to control an input multiplexer306 to sample the various signals to see what their state is. The PROM298 program output selects the input multiplexer 306 address and theoutput of the multiplexer stored as part of the next address register301. The fourth bit of program instruction from the PROM 298 is theBREADY signal to a cable timing control circuit 340 of FIG. 10g.

As discussed above, four of the eight address bits for each of the PROMS292, 294, 296, and 298 come from the next register address 300. A fifthaddress bit, SRRA4, comes from the output of the input multiplexer 306through part of the next adress register 301. The remaining threeaddress bits of the PROMS 292-298 are controlled by the signals RA0,RA1, and RA2 which come from the input/output port of the ROMcombination chip 206 of the microprocessor circuit. The signals RA0, RA1and RA2 are fed through inverters 308, 310 and 312 through a PROMcontrol bus 314 to the inputs of the PROMS 292-298. A fourth signal,RA3, from the ROM combination chip 206 is fed to a flip-flop 316controlled by a 5 megahertz clock signal to generate a reset signal RSTMwhich goes to the next address register 300 and a reset signal RSTMwhich goes to the output latch 302. The RA3 signal allows themicroprocessor 200 to turn off the ROM sequencer 290 when the ROMsequencer 290 has finished a particular function requested of it.

The microprocessor 200 controls the ROM sequencer 290 by the three-bitcommand RA0, RA1 and RA3 which specifies the program function to beperformed, setting a 0 in the RA3 bit which will release the ROMsequencer 290 by taking away the reset. When the ROM sequencer 290finishes performing its function, it sets the "STOP" bit at the outputlatch 302 which the microprocessor circuit can sample through the RAMcombination chip 202, and the ROM combination chip 206 responds byresetting the flip-flop 316, turning the ROM sequencer 290 off. Thereset bit RSTM also serves as a fail-safe mechanism by allowing the ROMsequencer 290 only a ceertain amount of allotted time to perform itsfunction. If too much time elapses, then the microprocessor circuitperforms an error recovery procedure by unconditionally resetting theROM sequencer 290.

The ROM sequencer 290 includes a bus cycle counter 318. The bus cyclecounter 318 determines how many bus transactions have occurred by beingincremented by the signal INCDMA every time a bus transaction occurs. Byselecting a particular one of the Q outputs of the bus cycle counter318, QA, QB, QC, and QD, the counter can be adjusted to count by 2, 4,6, or 8. Bus cycle counter 318 functions to prevent the ROM sequencer290 from monopolizing time on the Intel bus when the ROM sequencer 290is doing a bus block transfer. During a bus block transfer the ROMsequencer in effect locks out the other Universal Control Boards on thatbus. Bus cycle counter 318 causes the ROM sequencer 290 to periodicallygive up control of the bus so that some of the Universal Control Boardcan use it. The output signal from the bus cycle counter 318 is theBUSCOUNT signal to one input of the input multiplexer 306.

The input multiplexer 306 allows the ROM sequence 290 to sample thestate of a number of functions. An AND gate 320, receiving input signalsMUXCON and LOCK, has its output applied to one input terminal of theinput multiplexer 306. The DONE signal from the cable timing controlcircuit 340 is applied to another input terminal of the inputmultiplexer 306. The CONNECT signal from the output of the contentionlogic circuit 460 is applied as another input signal of the inputmultiplexer 306. The DMACOMP signal is from the bus timing controlcircuit 540; another input signal. The WCZERO signal from the word countregister 238 is also applied as an input signal.

The final input signal to the input multiplexer 306 is the BOTHD signalfrom a flip-flop 322. Flip-flop 322 has one pin connected to the outputof AND gate 324, having its two inputs connected to the DONE signal fromthe cable timing control circuit 340, and the DMACOMP signal from thebus timing control circuit 540. The two "DONE" signals are connected tothe input of the AND gate 324 to set the flip-flop 322. When the ROMsequencer 290 samples the input connected to the BOTHD signal of theinput multiplexer 306, it can reset the flip-flop 322 by the RDONEsignal originating from the output latch 302 and fed through an inverter326. The flip-flop 322 may also be reset by the signal RST2 from thereset circuitry 210.

A clock circuit 330 takes a ten (10) megahertz signal through aninverter 332 and feeds it through the flip-flop 322 to the ROM sequencer290. The ten (10) megahertz clock signal is also fed through anotherinverter 334 to a divide-by-two flip-flop 336 to generate a 5 megahertzclock signal (5 MCK) and an inverted 5 megahertz clock signal (5 MCK)for use elsewhere on the Universal Control Board.

As shown in FIG. 10g, cable timing control circuit 340 participates inthe bus timing on the cable by originating one of the two signals on thecable and sampling the other. The signal DMAOUT is an output commandsignal generated by the cable timing control circuit 340 and the DMAINsignal originated on the cable bus driver circuit. The BREADY signal isderived from the fourth output bit of the PROM 298 of the ROM sequencer290 (FIG. 10f) and is connected to the inputs of NAND gates 324 and 344.A second input of the NAND gate 342 is connected to the WRITE signalfrom the ROM combination chip 206 and the WCZERO from the inverter 280of the word count register 238. The output of the logic NAND gates 342and 344 are fed through an OR gate 346 to produce the READY outputsignal as one input to the D input of a D-type flip-flop 347. Theflip-flop 247 has its Q output connected to one input of a three inputNAND gate 348 and the clock input thereof connected to the ten magahertzclock. The NAND gate 348 also has its input tied to the DONE signal feedback from the output of the cable timing control circuit 340 and theDMACOMP signal from the output of the bus timing control circuit 540(FIG. 10m). The output of the NAND gate 348 is fed through an inverter350 to one pin of an input multiplexer 352. The input address of themultiplexer 352 is controlled by the state lines STB0, STB1 and STB2 asthe output of a counter 354. Counter 354 essentially reflects the stateof the cable timing control circuit 340. The input multiplexer 352 issampling the DMAIN signal fed through flip-flop 356 which generates theoutput signals DMAINSY and DMAINSY as the inputs to multiplexer 352.

The output of the input multiplexer 352 goes to an output multiplexer358 to allow certain signals to occur when the proper input is detected.The output multiplexer 358 waits in state 0 until it receives a logic 1from the output of the input multiplexer 352 which would cause theoutput multiplexer 358 to have an output on its state 0, causing a STOYsignal output. The STOY output signal goes through OR gate 360 andinverter 362 to reset the DONE signal from the output of a flip-flop364. The STOY signal is also fed through OR gate 366 to set the DMAOUTsignal at the output of flip-flop 368. The presence of the DMAINresponse from another Universal Control Board is sampled by the inputmultiplexer 352, and if it is in state 1 it causes the outputmultiplexer 358 and the signal ST1Y to be fed through OR gate 370 andinverter 372 to pin K of the flip-flop 368, causing DMAOUT to be reset.The input multiplexer 352 will change state upon a negative responsefrom the other end of the cable of DMAIN going away, indicating thatinformation has been taken off the cables. The change in state of theinput multiplexer output 352 may cause the state 2 output, ST2Y, to begenerated by the output multiplexer 358 which is fed through the OR gate374 to set the DONE output on the DONE flip-flop 364. The DONE signal isfed back to the input multiplexer 306 of the ROM sequencer 290 toindicate that the byte successfully moved to the other Universal ControlBoard. The output multiplexer 358 also has an output signal ST3Y fedthrough OR gate 376 and inverter 378 to reset the counter 354.

The sequence described above for setting and resetting the DONE andDMAOUT signals is basically the same whether the cable timing controlcircuit 340 is in the slave or master mode. The master mode operationwas described above where the DONE flip-flop 364 and DMAOUT flip-flop368 were set and reset by the signals ST0Y, ST1Y and ST2Y from theoutput multiplexer 358.

If the cable timing control circuit 340 is to operate in the slave mode,which means it is receiving a byte of data to be transmitted down acable from another Universal Control Board, the slave signal will begenerated from the ROM combination chip 206 to control the counter 354.The slave signal input to the counter 354 causes it to start out instate 4. The ST4Y signal is fed through one input of OR gate 360 andinverter 362 to reset the output of the DONE flip-flop 364. Responsefrom the control board on the other end of the cable is the DMAIN signalsampled by the input multiplexer 352 to cause a state 5 output at theoutput multiplexer 358. The ST5Y signal is fed through the OR gate 366to set the DMAOUT flip-flop 368. The cable timing control circuit 340then waits for the DMAIN signal to go down which is detected by theinput multiplexer 352 causing the state of the output multiplexer 358 tochange to state 6. The ST6Y signal is fed through OR gate 374 to set theDONE output of flip-flop 364 and also fed through OR gate 370 andinverter 372 to reset the output of DMAOUT flip-flop 368. The outputmultiplexer 358 slave mode also has the output signal ST7Y fed throughOR gate 376 and inverter 378 to reset the counter 354.

FIGS. 10h and 10i illustrate the circuit providing the data path for themovement of a piece of data. Bus data drivers/receivers 400 and 402 areintegrated circuit chips which function as translation devices for dataflowing between the bus and the Universal Control Board. The bus datadrivers/receivers are controlled by NOR gate 404 having one of its inputfrom the CONNECT signal from a contention logic circuit 460 (FIG. 10k)and an input from the BDSEL (board select) signal from an address decodecircuit 490 (FIG. 10-1). A NOR gate 406 also controls the datadrivers/receivers 400 and 402 and has its inputs connected to the RENsignal and the IOR signal.

The data DB0-DB7 connected internally on the Universal Control Boardmoves through data bus 408 to command/status register of RAM combinationI/O Chip 204 (FIG. 10b) and to the input of holding registers 410 and412. The STROBE signal from the bus timing control circuit 540 (FIG.10m) is fed through inverter 414 to a register 410. The INCDMA signaland READ signal are the inputs of NAND gate 416 having its output REN tothe register 412. The REN signal is also fed through an inverter 418 andthrough one input of the NOR gate 406. The output of the NOR gate 406 isconnected to the bus data drivers/receivers 400 and 402.

Holding register 420 has its input connected to the output of holdingregister 410 to generate an overlapped transaction. A byte of dataloaded into register 410 from the bus is immediately transferred to theregister 420, so that register 410 is ready to read another byte of datafrom the bus. The cable timing control circuit 340 is runningsimultaneously with the bus timing control circuit 540 to send bytes ofdata through the cable while the bus timing control circuit 540 isreading bytes of data from the bus. Holding registers 410 and 420 createthis overlapped transaction when moving data from the bus memory to thecable. The output of register 420, IB0-IB7, is placed on cable bus 422to cable bus drivers 424 and 426, which serve as translation devices totake the data from the internal environment of the board and put it onthe external environment of the cable. A parity generator 428 takes theeight data bits IB0-IB7 and generates a ninth data bit, IB8, which is anodd parity representation of the rest of the data. The IB8 output of theparity generator 428 is input to a line driver 429 to generate the PARsignal. A RESSTBIN signal is also input to the other D-input of the linedriver 429, the B output of which is connected to an optional jumper 431to generate a RESSTB signal and a SYSRESET signal. The jumper 431 isadded to make the connection, as shown by the dashed lines, to generatethe output signals.

The holding registers 412 and 420 provide an overlapped condition ininput, when data is moving from the cable into the bus memory. Datareceived by cable drivers/receivers 424 and 426 is transferred through aregister 430 to a bus 432 as data bits OR0-OR7 as the input of holdingregister 420. The data stored in the holding register 420 is immediatelymoved into the holding register 412, so that register 420 is availableto do another transaction simultaneously, moving the first data byteinto holding register 412. Thus, holding register 420 switches functionsdepending on whether the system is in the input or output function inorder to provide the overlapped condition.

A parity checking generator 434 takes the eight data bits RD0-RD7 fromthe cable drivers/receivers 424 and 426 to generate a ninth data bit,RD8, which is an odd parity representation of the rest of the data.Generation of the parity bit is stored in flip-flop 436 which generatesthe signal PARER to the RAM combination chip 202 of the microprocessorcircuit.

The holding register 420 is clocked by three different functions throughan OR gate 438. One function is the input function when the system isreading from the cable. In this input function, the READ signal and theDMAINSY signal are the inputs to a NAND gate 440, which has its outputconnected to the input terminal of the OR gate 438. In the outputfunction, the WRITE and G1012 signals are connected to the inputterminals of NAND gate 442 which has its output connected to OR gate438. The third function of the holding register 420 involves single bytetransfers on the bus, transfers which do not involve the cable. TheDATACLK signal from the RAM combination chip 202 is fed through oneinput terminal of the OR gate 438.

A bus address switch 450 is also connected to the cable bus 422 toprovide a unique address for a Universal Control Board. Themicroprocessor circuit through its RAM combination chip 202 has anoutput signal RDSWT connected to the bus address switch 450 to read thepreset switches which are the input to the bus address switch 450. Theswitch 450 has eight inputs labeled SW0, SW1, SW2, SW3, SW4, SW5, SW6and SW7 referring to the number of switches present. By selectivelygrounding a combination of switches, a unique code can be manuallyplaced into an individual Universal Control Board. This is part of theinitialization function of the microprocessor circuit.

The microprocessor circuits of the Universal Control Boards communicatewith one another to determine which Universal Control Boards have accessto the cable bus and to determine whether they are in the master orslave mode. The DATAIN, IINTR and SDATAIN signals from themicroprocessor circuit are switched through a control multiplexer 452 toswitch the three signals to either a master cable bus driver/receiver454 or a slave cable bus driver/receiver 456. If microprocessor 200 isin the master mode, the control signals are switched to the master cablebus driver/receiver 454. If the SLAVE.1 signal is received by thecontrol multiplexer 452, the microprocessor 200 is in the slave mode andthe control signals are directed to the slave cable bus driver/receiver456.

In the master mode, the driver/receiver 454 is driving the interruptline, INTR, and the request lines, DMAREQ and DATAREQ. In the mastermode, the slave cable bus driver/receiver is receiving the attention,ATTEN, signal as well as the response signals, DMARESP and DATARESP. Inthe Universal Control Board in the slave mode, just the reverse happens.The master driver/receiver 454 is receiving the interrupt signal, INTR,and the request signals, DATAREQ and DMAREQ. The slave driver/receiveris driving the attention signal, ATTEN and the response signals, DMARESPand DATARESP.

As shown in FIG. 10k, access to the bus is controlled by contentionlogic circuit 460. The contention logic circuit 460 is controlled bythree signals, BUSY and BPRN from the bus and BUSREQ from the ROMsequencer 290. The BUSY signal is an indication that the bus is busywith a transaction in progress. The BPRN signal is an indication ofwhether or not the Universal Control Board has priority. The BUSREQsignal is generated by the ROM sequencer 290 when it is doing eithersignal or block mode transfers. The OVERRIDE signal is from aninput/output port of the ROM input/output port chip 206. A bus requestflip-flop 462 may be set by either the BUSREQ signal or the OVERRIDEsignal. The BUSREQ signal is fed through an inverter 464 to one input ofan OR gate 468 having its second input terminal tied to the OVERRIDEsignal. The output of OR gate 468, SBREQ, sets the bus request flip-flop462. The BREQ signal from the output of the flip-flop 462 is fed throughinverter 470 to appear as the signal BREQ which goes on the bus to someexternal logic which will arbitrate bus priority. This externalcontroller determines priority and upon receipt of priority for therequesting Universal Control Board the BPRN signal is received by thecontrol board fed through inverter 472 to one input terminal of NANDgate 474. The BREQ signal is fed back through the output of the busrequest flip-flop 462 to another input gate of the NAND gate 474. Whenthe bus is not longer busy, the BUSY signal is fed through an inverter476 and inverter 478 to the third input terminal of NAND gate 474. Theoutput of NAND gate 474 is the output signal SCON fed through aninverter 480 to set a connect flip-flop 482. The output connect signalis fed back through inverter 484 to generate the BUSY signal. The onlyway to reset the bus request flip-flop 462 is for the bus request signalto be reset. A BUSCLK signal is received from the bus and fed through aninverter 486 as the bus clock signal to the bus request flip-flop 462and the connect flip-flop 482. The connect flip-flop 482 has an overridecircuit 487 attached to the input thereof. The override circuitgenerates the signal CONOVRIDE to connect a pullup to the flip-flop 482.

As shown in FIG. 10-1, an address decode circuit 490 functions to decodethe addresses AA0-AA7 from address drivers 262 and 264. Address signalsAA4-AA7 are fed through address decoders 492 and 494 to generate outputsignal BDSEL, the board select signal. The other four signals AA3-AA0are fed through address decoder 496 to select one of three functions onthe board. The input/output reset function, the IORST signal, is fedthrough an inverter 498 and one input terminal of NAND gate 500. Theother input of NAND gate 500 is from the IOW signal from the bus timingcontrol circuit 540. The input/output reset function indicates that someother controller on the bus desires this Universal Control Board to bereset, and the IORST signal is fed to the reset circuitry 210 describedhereinabove.

The remaining two functions decoded by the address decoder 496 are usedto communicate with one of the input/output ports of the RAMinput/output combination chip 204. The integrated combination chip 204can be configured through software to function as either a statusregister or a command register. The command register function is fedfrom the address decoder 496 through an inverter 502 to one inputterminal of NAND gate 504. The second input terminal of NAND gate 504 iscontrolled by the IOW signal. The output of NAND gate 504 is the CMDWsignal to port A of the RAM combination I/O chip 204. The output fromthe inverter 502 is also fed to one input of NAND gate 506 having itsother input connected to the IOR signal from the bus timing controlcircuit 540 (FIG. 10m). The output of NAND gate 506 is the signal STATRwhich goes to port B of the RAM combination I/O chip 204.

The command register functions to allow some other control board to loaddata into the register so that it can be read and responded to by themicroprocessor circuit. The status register functions to allow themicroprocessor circuit to store information here and some otherUniversal Control Board can read that information through the bus andthe address decode circuit 490.

A third function of the address decoder 496 is an output fed throughboth input terminals of NAND gate 508 which has its output applied asone input to NAND gate 510. The outputs of NAND gates 506 and 510 arefed to the inputs of OR gate 512 which has its output connected to theinput of NAND gate 514 which has its output connected to a data businterface device 516.

Reviewing the three commands implemented through the address decoderdevice 496, the output of NAND gate 504 loads a byte of data into thecommand register of the RAM combination I/O chip 204. The output of NANDgate 506 creates and simultaneously resets the status register of theRAM I/O chip 204, while the output of NAND gate 510 reads the statusregister of chip 204 without resetting it. The output of the status andcommand registers, DB0-DB7, is placed on the DB data bus 408 (FIG. 10h).

A bus slave timing circuit 520 receives the strobes IOWC and IORC fromthe output of the bus timing control circuit 540. The IOWC signal is fedthrough inverters 522 and 524 to one input of OR gate 526. The IORCsignal is fed through inverters 528 and 530 to the other input of ORgate 526. The output of OR gate 526 is input to shift register 532 togenerate an output XACK fed through an inverter 534 to be conditioned asthe signal XACK. The XACK signal is an acknowledgement to the bus thatread and write strobes have been detected and the board select addresshas been detected. The board select signal is fed through an inverter536 to the shift register 532. Shift register 532 also has a clocksignal, CCLK, fed through an inverter 538.

FIG. 10m illustrates the bus timing control circuit 540. A NAND gate 542has its input connected to the READ signal and the DMASTART signal fromthe ROM sequencer 290. The output of the NAND gate 542 is connected toone input terminal of OR gate 544. The second input terminal of the ORgate 544 is connected to the output terminal of AND gate 546, having itsinput terminals connected to the WRITE signal, the WCZERO signal and theDMASTART signal from the ROM sequencer 290.

The output of the OR gate 544 sets flip-flop 547. The output offlip-flop 547 is the origin of the INCDMA signal and it is also fedthrough an inverter 550 for the AEN signal. The output of the flip-flop547 also controls the input of flip-flop 552 for setting the DMACOMPsignal to be fed to the ROM sequencer 290. The output of a flip-flop 548is used to set one input of AND gate 554.

The XACK signal from the bus slave timing circuit 520 is fed through aninverter 556 to set a flip-flop 558. One output terminal of theflip-flop 558 is connected to a second flip-flop 560 having its outputfed back to the K terminals of the flip-flops 558 and 560. The secondoutput terminal of the flip-flop 558 is identified as the RACK signalconnected to the second input terminal of an AND gate 554.

The output of the AND gate 554 is connected to one input terminal of ANDgate 562 and AND gate 564. The second input terminal of the AND gate 562is the MEMCY signal from the ROM combination I/O chip 202. The output ofAND gate 562 is connected to the first input terminal of AND gates 566and 568. The second input terminal of AND gate 566 is the WRITE signalfrom the ROM combination I/O chip 206, and the second input terminal ofAND gate 568 is the READ signal also from the ROM combination I/O chip206. The output of AND gate 566 is fed through an inverter 570 andidentified as the MRDC signal, and the output of the AND gate 568 is fedthrough inverter 572 identified as the output signal MWTC.

The AND gate 564, having one input terminal connected to the output ofAND gate 554, has a second input terminal connected to the IOCY signalfrom the RAM combination I/O chip 202. The output of AND gate 564 is fedto input terminals of AND gates 574 and 576. The second input terminalof the AND gate 574 is the READ signal, and the second input terminal ofthe AND gate 576 is the WRITE signal. The output of AND gate 574 is fedthrough an inverter 578 and is the IOWC signal used as an input to thebus slave timing circuit 520. The output of the AND gate 576 is fedthrough an inverter 580 which has as its output the IORC signal used asanother input to the bus slave timing circuit 520.

Referring now to FIG. 10n, there is illustrated a schematic diagram ofthe reset circuitry for individually resetting one of the UniversalControl Boards that is connected to the VMS system. An inverter 582 hasthe input thereof connected to one of the switch inputs on the busaddress switch 450 (FIG. 10h), and the other input thereof is connectedto one input of NOR gate 584. The output of the NOR gate 584 isconnected to the input of an inverter 586, the output of which is inputto the jumper board 431 of FIG. 10i. A NOR gate 588 has one inputthereof connected to the input of the inverter 582, the other inputthereof connected to the output of the inverter 586 and the outputthereof connected to one input of a NOR gate 590. The output of the NORgate 590 is connected to the input of an inverter 592 which has itsoutput connected to the "B" input of an IC 594. The IC 594 is a parallelshift register, of which the output is conditioned by an inverter 596 toprovide the output signal INIT . The output of the inverter 592 is alsoconnected to the CLEAR input of the IC 594. The clock input of the IC594 is connected to the 5MCK. A comparator 598 receives the inputs RD0,RD1, RD2, and RD3 on the A0-A3 input thereof. And the SW0, SW1, SW2, andSW3 signals on the B0-B3 inputs thereof. The output of the comparator598 is input to the other input of the NOR gate 590. The comparator 598compares the bit word on the input A0-A3 with the bit word on the inputB0-B3. The inputs to the B0-B3 input are taken from the inputs to thebus address switch 450 (FIG. 10h) and denote the unique code for a givenUniversal Control Board. When the A0-A3 inputs correspond to that on theB0-B3 inputs, the output is activated and the B input of the IC 594 isactivated. The switch signal SW7 that is connected to both the input ofthe inverter 582 and the input of the NOR gate 588, denotes theUniversal Control Board that is selected as the master board.

In the VMS system, one of the Universal Control Boards is designated asthe master board and input SW7 of the bus address switch 450 isgrounded. This places a high logic signal on the A input of the IC 594and allows the INI to control the operation of the NOR gate 588. If theboard is not designated as the master board, a high signal is input tothe inverter 582 and the NOR gate 588 which activates the NOR gate 584and deactivates the NOR gate 588. This prevents the INI signal fromactivating the IC 594 and allows the comparator 598 to control the NORgate 590, thus controlling the IC 594. The reset circuitry of FIG. 10nallows the VMS system to selectively reset only one of the UniversalControl Boards without resetting all at one time.

The VMS 10 utilizes several microprocessor controlled Universal ControlBoards connected to one bus instead of a single minicomputer. The Intelbus is the main bus which connects all the microprocessors together. TheUniversal Control Board has two distinct capabilities for moving dataaround in the VMS 10. First, the microprocessor 200 of the UniversalControl Board may transfer data in single bytes in and out of the busmemory at a relatively slow rate to communicate with othermicroprocessors 200. Secondly, the Universal Control Board may alsocontrol the transfer of data in block form at a very high rate of speedthrough the cable or data bus interconnecting the Universal ControlBoards. The ROM sequencer 290 has the function of coordinating thetiming of the transfer of information from one cable to another cablewith the microprocessor 200 instruction transfers to or from the bus.

The VMS 10 is an advanced communication system for audio signals,including facsimile, data, cryptographic and voice signals. The VMS 10implemented in the preferred embodiment is described above in connectionwith voice signals, but the concept of the communication system hasapplication for other audio signals as well. The VMS 10 of the preferredembodiment allows users to deposit voice messages which are recorded andlater delivered to the intended recipients. In addition, users may callthe VMS 10 at any time and inquire if any messages have been depositedfor them. The VMS 10 may also answer a telephone while the user isabsent or otherwise unavailable to receive the call and record a voicemessage for subsequent delivery to the user.

While the VMS 10 is intended primarily for use within medium to largecorporations, it may be effectively used to improve the operatorefficiency of any communication system. It offers an improved method ofcommunications and at the same time it provides an excellent return oninvested capital, achieved through increased personnel productivity atall levels within the company, as well as through personnel reductionand elimination of many existing, costly communication facilities. TheVMS 10 also provides a number of usage reports to monitor the operationof the system.

The three basic features of the VMS 10, DEPOSIT, DELIVERY and INQUIRY,have been simplified to provide an easy to use system. The VMS 10includes instructional and "canned" messages ("Voice Message System","VMS", and "Voice-messages" are trademarks of Applicants' assignee, VMX,Inc.). Each of the three basic features of the VMS 10 will be describedbelow.

FIGS. 11 to 14 represent the flow chart for the DEPOSIT feature of theVMS 10. "DEPOSIT" is the procedure by which one or more voice messagesare placed into the VMS 10 for subsequent delivery. Referring to FIG.10, the DEPOSIT procedure is initiated by dialing into the VMS 10 toaccess the system 600, causing the VMS 10 to answer 602 by playing acanned message, such as "This is VMS."

A timer is started when the VMS 10 answers a call and identifies itselfat step 602. The user then must complete the entire DEPOSIT processwithin a preset time interval (for example, 4 minutes). Approximately 30seconds before this interval expires the VMS 10 will begin signaling theuser with an alarm, such as a "beep" every 3 seconds. If the user hasnot completed the DEPOSIT operation by the end of the time interval, theVMS 10 will abort the DEPOSIT operation and terminate the user's accessto the system.

After the VMS 10 answers 602, the user then dials a unique authorizationnumber 604 for identification purposes to gain access to the system. TheVMS 10 will allow the user a preset amount of time to dial a signedauthorization number, e.g., 45 seconds. Upon entry of a validauthorization number, the VMS 10 responds with a short progress toneindicating it is ready to process an addressee 606. When all addresseshave been entered, the user dials an End-of-Address indicator, e.g.,"0," and VMS 10 will provide a recordmode "idle" tone, such as arepeating "beep-beep . . . " signal. The next step in the DEPOSITroutine 608 determines if the end of record indicator has been entered.If it has not, he returns to step 606 for the entry of an addresseenumber. If it has been determined that a "0" was dialed, the user dials"1", removing the VMS 10 idle tone which enables this to record a voicemessage 610. At the conclusion of the recording step 610, the user mayelect to either DEPOSIT another message 612, inquire for messages 614 orhang up 616.

In the system's step 606 in processing an addressee, the user may dialone or more addresses to which the voice messages are to be sent."Addressees" are generally no more than telephone numbers, localextension numbers, distant company locations, or "off net" long distancenumbers. A system parameter may be entered from the console to set themaximum number of individual addresses which may be entered. Inaddition, a distribution list code may be used as an address. This is athree digit address which is automatically translated by the VMS 10 intothe previously defined individual telephone numbers of the group. Theuser of the VMS 10 in this way may send a single voice message to anumber of people by using a single address, analogous to using adistribution list for a memo or letter. The VMS 10 will then deliver thevoice message independently to each person within the group.

The VMS 10's step 604 for processing a user ID is set forth in furtherdetail in FIG. 12. The procedure is initiated by the user dialing theidentification code digits 618. The user may dial an "*" 620, if hediscovers a dialing error before dialing the last digit. The VMSresponds with a single "beep-beep" tone 622 to acknowledge that the useris allowed to redial the identification code. The VMS 10 next validatesthe identification code of the user 624. In determining the validity ofthe code 626, the VMS 10 acknowledges if a valid code has been entered628 with an audible signal, such as a single "beep." This completes theuser-ID processing 604 to allow the user to proceed to process anaddressee 606 (FIG. 11). However, if the user identification code hasbeen determined to be invalid, the VMS 10 determines if this is thefirst or second invalid entry 630. If it was the first attempt to entera valid user code, the VMS 10 plays a canned message 632, such as: "TheID (₋₋) is not valid. Please try again." The program then returns theuser to program step 618 for redialing of the identification code. Ifthe second try for the validity test 630 determines that this is thesecond entry of an invalid code, the VMS 10 plays a canned massage andhangs up 634. The canned massage at step 634 would be: "The ID youentered is again not valid. Please dial (₋₋) for information orassistance. Thank you." There is an alternative to the progress toneprovided at program step 628 to the VMS 10's acknowledgement of a validID code. A canned massage may instruct the user as follows: "To deposita message, you may now dial the addressees. For any other function dialthe 3 digit special function code." The user may access the VMS 10through a special code to provide for verbal instructional commands inlieu of progress tones.

FIG. 13 is a flow chart of the process and addressee program step 606 ofFIG. 11. In the first program step 635, the user dials digits for anaddressee. If the user discovers a dialing error before dialing the lastdigit he may branch to program step 636 by dialing a "*" to delete theaddressee number. The VMS 10 responds with an audible signal, 638"beep-beep," and allows the user to redial the addressee. Upon theuser's entry of the digits for an addressee, the program provides forthe VMS 10 to validate the addressee 640. The program step 642determines the validity of the addressee. If a proper addressee code hasbeen entered, the VMS acknowldeges with an audible signal 644, "beep."If the user discovers a dialing error after dialing a complete addresseeand receiving acknowledgement from the VMS 10, he may branch to program646 by dialing "*" on a touch signaling phone or "7" on a rotary phone.The VMS 10 program next responds with an audible signal 650, "beep-beep"and allows the user to reenter at program step 635 to dial the digitsfor the addressee. If at the validity determination step 642, the VMS 10determines that an invalid addressee number has been entered, thesignal, "beep-beep-beep," and allows the user to redial the addressee.

Referring to FIG. 14, the record voice message block 610 of FIG. 11 isshown in greater detail. The VMS 10 emits a repetitive audible tone suchas an idle tone prior to the recording of any message. The user dials"1" in block 654 to remove the idle tone from the VMS 10 and to allowthe user to record a voice messge 656. During the speaking of the voicemessage, the following dial commands are available to control therecording procedure:

    ______________________________________                                        DIAL COMMAND   VMS ACTION                                                     ______________________________________                                        1              Start recording.                                               1              Stop recording and return the                                                 record mode idle tone.                                         3              Back up (approximately 10                                                     seconds) and start playing.                                    4              Back up to the beginning of the                                               voice message and start playing.                               9              Skip forward (approximately 10                                                seconds) and play.                                             99             Skip forward to end of recorded                                               data and return to the record                                                 mode idle tone.                                                ______________________________________                                    

Following the end of the voice message step 656, the user next dials anEnd-of-Messge indicator (EOM) at step 658 by dialing "5" for normalmessage delivery and "6" for priority delivery. The EOM can also be usedto activate the nondelivery notification (NDN) feature. This featureallows the voice message originator to be notified automatically if themessage is not delivered to the intended recipient the next businessday. If this happens, the voice message is automatically readdressed tothe originator, and the following "canned massage" appended to itsbeginning: "This is VMS, the following message was not delivered (thevoice message follows)." NDN is activated by dialing the EOM twice("55"), or ("66"). Upon the user's dialing the EOM digits in step 658,the VMS 10 responds with a "beep" at program step 660. At the end ofrecord voice message program step 610 the user has the three programoptions, as illustrated in FIG. 11 and described hereinabove.

The DEPOSIT function of the VMS 10 further provides for discarding thevoice message if the user hangs up prior to EOM. The VMS 10 DEPOSITprogram also provides for three different types of time periods whichare predefined for the customer at the time of system generation. Thesepredefined time periods may be subsequently changed from the systemoperator's console 104 of FIG. 6. The first of the three time periodsthe VMS 10 uses to monitor the message DEPOSIT process is an overallcall duration timer. About 30 seconds prior to the elapse of the messageDEPOSIT operation within the remaining time, the VMS 10 will abort andhang up. There is a second short duration time period that VMS activateswhile waiting for the user to dial a "parameter" such as the user IDstep 604, a single addressee in step 635, or dialing "0" to signal theend of addressees in step 608. Finally, a third predefined time periodis used by the VMS 10 to monitor the time that the user is in the recordmode idle state prior to the user dialing " 1" in step 654. This recordmode idle state is entered after dialing the "0" for the end ofaddressees code in step 608.

The DEPOSIT function also includes program means for negating one ormore numbers in a distribution code. For example, if a particulardistribution code equated to fifty individual telephone numbers, one ofthese numbers that the originator did not wish to send a message tocould be deleted for the entry of a suitable program code. After theentry, the distribution code will have the effect of negating thataddress from a list of numbers on the distribution code to receive thatvoice message.

In addition, the DEPOSIT function of the VMS 10 is also programmed toallow a user to call the VMS 10 by a Special Function Code to turn on oroff the Enhanced Verbal Commands and Reply (EVCR). The user's selectionof the EVCR mode causes the VMS 10 to play prerecorded instructionalmessages in place of progress of error tones, e.g., tones which mightrelate to incorrect user ID's and addresses.

"DELIVERY" is the second of the three system features of the VMS 10,which enables voice messages to be played to their recipients. FIG. 5illustrates a flowchart of the program of the VMS 10 for the messageDELIVERY function 670. In initial step 672 of the program the VMS 10calls the message recipient by dialing the telephone of the recipient.In the next step 674, the user answers and the VMS 10 may identifyitself by playing canned massage as follows: "This is VMS. There are ₋₋messages for you. Please dial your authorization number if you wish toreceive them. Thank you." If the message addressee had not answered theinitial telephone call from the VMS 10, the VMS 10 is programmed to waitand attempt to redeliver the message at a later time. Likewise, if themessage addressee's telephone had been busy, the VMS 10 would again beprogrammed to attempt to deliver the message a predetermined number oftimes at predetermined time intervals. The number of attempts and timeintervals between each of the attempts by the VMS 10 to deliver themessage are programmed parameters that are definable by the customerthrough the system console 104 of the VMS 10.

When the VMS 10 establishes contact with the message addressee, themessage addressee responds by dialing his unique authorization numberand the VMS 10 processes the user's ID at step 676. After the processuser ID has been accepted at program step 676, the VMS 10 emits an idletone at the program step 678, indicating the non-lay mode. The user ormessage addressee then dials "2" to begin playing the voice messageprogram 680.

During the playing of a voice message, the following dial commands areavailable to the message addressee to control the VMS 10 messagedelivery 670:

    ______________________________________                                        DIAL COMMAND   VMS ACTION                                                     ______________________________________                                        2              Start Playing.                                                 2              Stop playing, followed by                                                     nonlaying indicator, a periodic                                               "beep."                                                        3              Back up and play approximately                                                the last 10 seconds.                                           4              Back up to the beginning of the                                               voice message and start playing.                               9              Skip forward approximately 10                                                 seconds and play.                                              99             Skip forward to end of message.                                ______________________________________                                    

At the conclusion of the voice message, the VMS 10 is programmed to playsome audible tone, such as three short "beeps" indicating the end ofmessage, or an EOM canned message if EVCR is turned on. The VMS 10 isthen programmed to wait approximately 5 seconds for the next user action682. The message addressee then has the option of taking no action 684or initiating some action with the VMS 10 through one of the specialfunction codes redirect 686, reply 688, save 690 and file 691.

If the user decides to take no action 684, the VMS 10 is programmed todetermine whether there are more messages 692. If there are no moremessages, the VMS is programmed to play a canned message and hang up694. Thus a suitable canned message could state: "This is VMS. Thisconcludes your voice message delivery. Thank you." If the VMS 10determines that there are more messages for the addressee 692 the VMS 10indicates such message to addressee at program step 696 by playing asuitable canned message, such as: "This is VMS. Here is another messagefor you." The program is then returned to step 678 for the VMS 10 toadmit an idle tone prior to playing a voice message step 680.

The message addressee can enter the VMS 10 through one of the specialfunction codes redirect 686, reply 688, save 690, and file 691. Theseprogram steps are described below.

The VMS 10 is ordinarily programmed if a message addressee hangs upduring the playing of a voice message. That message and all otherundelivered messages will be delivered at a later time or could beavailable to the message addressee through the INQUIRY function (FIG.21).

The VMS 10 program routine for the process user ID step 670 isillustrated further in the flowchart presented in FIG. 16. The userfirst dials digits for its identification code step 697. The systemenables a user to dial "*" in step 700 if he discovers a dialing errorbefore dialing the last digit. If the user dials "*" 700, the VMS 10responds with an audible tone, "beep-beep" at step 702 returns the userto step 697 for reentry of the authorization code. After the user hasentered his authorization code, the VMS 10 validates the ID at programstep 704. The VMS 10 determines the validity of the ID at step 706, andif it determines that the user has entered an invalid ID then itdetermines at step 707 whether this is the first or second attempt toenter a valid ID. If its is the first attempt, the VMS 10 plays asuitable canned message at step 708 and returns the user to program step696 for reentry of the authorization code. A suitable canned messagewould be the following: "The ID (₋₋) is not valid. Please try again." Ifthe VMS 10 determines at step 707 that this is the second attempt toenter a valid ID the VMS 10 proceeds to play another canned massage step710 and hangs up. A suitable canned message upon the detection of thesecond entry of an invalid user ID would be the following: "The ID youentered is not the correct one for the message recipient. Please tryagain."

The VMS 10 at program step 706 determines that a valid user ID has beenentered. The VMS 10 next compares the ID with that of the recipient atstep 709. This concludes the process user ID processing of program 676of flowchart of FIG. 15. If the VMS 10 at step 712 determines that theID is not the same as that of the recipient, then program step 714determines whether this is the first or second attempt to determine ifit is the recipient's identification code. If it is the first attempt,the VMS 10 at step 716 plays a suitable canned message and returns theuser to program step 697 for reentry of the user identification code. Asuitable canned message at program step 716 could be the following: "TheID you entered is not the correct one for the message recipient. Pleasetry again." If the VMS 10 determines that this is the second unsucessfulattempt in comparing the recipient's ID, the VMS 10 at program step 718plays a suitable canned message and hangs up. The VMS 10 at program step718 will play the same canned message included in program step 710.

FIG. 17 illustrates the play voice message subroutine 680 of the messagedelivery program 670 of FIG. 15. The play voice message subroutine 680begins with the user dialing "2" in step 720 to remove the VMS 10 idletone and initiate the playing of the voice message. The VMS 10 plays thevoice message to the user at step 722, during which time the user cancontrol the playback process by dialing certain digits on his telephone,as described above.

At the conclusion of the voice message, the VMS 10 emits an audible toneat step 724 to indicate end of message. The VMS 10 is returned toprogram step 682 of FIG. 15.

As described above, the VMS 10 waits approximately five seconds for thenext user action 682 which enables the user to enter certain specialfunction codes if he so chooses to access the VMS 10. The REDIRECTspecial function code (SFC) subroutine program 686 is illustrated inFIG. 18. The user enters a three digit SFC at redirect program step 726.The VMS 10 responds with a progress tone at step 728, such as a "beep."The user then dials the addressee at program step 730, and the programproceeds through a subroutine as illustrated in FIG. 13 of the messagedeposit flowchart. The program then determines at step 732 if a "0" wasdialed at end of addressee number. If it was not entered, the user isreturned to program step 730 for dialing an addressee. If the user hasdialed a "0" he may record a voice message at program step 734, whichvoice message is appended to the beginning of the original voice messageand delivered to the newly designated addressees. The original voicemessage with recipient's comments then will be sent to the newaddressees. The program step 734 follows the subroutine of the messagedeposit flowchart of FIG. 14. The user is then returned to the VMS 10program step 682 of FIG. 15, which allows the user the opportunity againto select another special function code.

The REPLY special function code (SFC) flowchart 688 is illustrated inFIG. 19. The message addressee which desires to reply to the voicemessage immediately may enter a special three digit SFC at program step736. The VMS 10 responds with a progress tone at program step 738, whichenables the user to record a replay message at program step 740, whichfollows the flowchart subroutine of the message DEPOSIT flowchart ofFIG. 14. The REPLY SFC feature enables the user to have a voice messagedelivered to the voice message originator without having to call the VMS10 to enter an authorization number and the address of the originator.After the reply message has been entered, the VMS 10 returns to itsnormal procedures at program step 682 of FIG. 15 starting with playingthe end of message indicator.

Following the program step 682, the user may also elect to enter thefile special function code 691 for the verbal file folder. This isaccomplished by dialing the code for the verbal file folder plus theverbal file folder number (0 through 99). A copy of that message willthen be retained in one of the 99 verbal folder categories along withall other voice messages in that verbal file folder for later retrieval.

FIG. 20 illustrates the SAVE SFC program flowchart of the messagedelivery function 670 of FIG. 15. At the conclusion of the end ofmessage indicator program step 682, the user may decide to save a voicemessage for later retrieval. The user may accomplish this by dialing theSAVE special function code which causes the voice message to be savedfor a predetermined period one complete business day. The user simplydials the three digit special function code for the SAVE program step742, and the VMS 10 responds with a progress tone at program step 744.The VMS 10 is programmed such that undelivered messages which did nothave nondelivery notification (NDN) will be discarded at the midnightfollowing their retention for one full business day. The appropriatesummary report will be created by the VMS 10 for each message sodiscarded, showing the originator ID, input time and date and deliverytime and date.

FIG. 21 illustrates the INQUIRY function 750 which enables the user tocall the VMS 10 to determine if there are any messages for him. If thereare no messages, the VMS 10 so notifies the user. If there are messages,they are delivered immediately.

The INQUIRY function 750 begins with the user dialing the VMS 10, andthe VMS 10 program responds at step 752 with an acknowledgment in theform of a short progress tone or a canned message. The user then entersan identification code at step 754 to be processed in the mannerpreviously set forth in the message DEPOSIT flowchart of FIG. 12. Theuser next dials the INQUIRY special function code at step 756, and theVMS 10 makes the determination at program step 758 if there are anymessages for the user. If there are none, the VMS 10 plays anappropriate canned message at program step 760 and gives the user theoption to deposit a message. If the program step 758 determines thatthere are any messages, the VMS 10 plays an appropriate canned messageat step 762, which might include an instruction advising the user todial a particular digit if he wishes to receive the messages. The VMS 10will then play the voice message at program step 764 in the same mannerpreviously set forth in the message DELIVERY flowchart of FIG. 15. Atthe end of message indicator, the VMS 10 will determine at program step766 if there are any more messages for the addressee. If there are none,the VMS 10 plays an appropriate canned message at program step 768,allowing the user the option to deposit any messages with the VMS 10. Ifthere are more messages, the VMS plays an appropriate canned message atprogram step 770 and returns the user to the play voice message routine764 of the flowchart.

FIG. 2 contains a VTOC (Visual Table of Contents) of all the programsincluded in the VMS system software 800. At the top level these programsare divided into six categories as follows:

(1) ROM--resident programs 802,

(2) "System support" programs 804,

(3) Master processor utility programs 806,

(4) Master processor "online" programs 808,

(5) Slave processor "online" programs 810,

(6) Call processor "online" programs 812.

All of these programs run in the 80/30 SBC's (Single Board Computers)that are used to implement the call processor in the call processorsubsystem 62 or the master and slave processors in the administrativesubsystem 60.

80/30 ROM-Resident Programs

The processor programs are contained in read-only memory (ROM), and areused in all three catagories of processors ("master," "slave," and"call"). An operating system nucleus 814 is the resident operatingsystem that controls the multi-tasking environment of the applicationprograms. A Basic Monitor 816 is the program that receives control onpower-up, or system reset. It provides some simple CRT-based functions,such as examining and modifying the contents of memory cells, and alsocontrols memory loading/dumping. A Memory Load/Dump 818 operates undercontrol of the Basic Monitor 816. It provides the functions of loading"memory-image" data into memory from disk, and dumping memory to disk.An area of the disk is reserved for these memory-images that are used bythis program.

80/30 "System Support" Programs

The System Monitor 820 program is used only in the master processor. Itsfunction is to load programs from disk into memory as instructed to doso by an operator at the console CRT 104. The Overlay Manager program822 is a support function that is used to load individualprogram-segment overlays into memory. The Memory Allocation Managerprogram 824 is a support function that manages a "pool" of memory spacefrom which blocks (of memory space) are dynamically allocated torequesting programs.

80/30 Master Processor Utility Programs

The Master Processor Utility Programs 806 are not normally used when theVMS system 10 is online. The functions they provide can be regarded as"tools" that are used to maintain, update, and debug the system. A DataBase Creation program 826 is used to create a completely new user recorddata base on the system disk. A Data Base Update Program 828 and DataBase Print Program 830 will print the contents of the user records inthe data base on the system line printer 108 (See FIG. 6). A Memory DumpAnalyzer program 832 will display on the console CRT 104 or the lineprinter 108 the contents of a memory dump (or a portion thereof) asrecorded in one of the disk storage areas reserved for memorydump/loads. A Disk Utility Program 834 provides a variety of functionsthat are concerned with moving, saving, and restoring information on thesystem disks 120; for example, transferring information from one area toanother in disk storage, or transferring data from disk storage to/fromdiskettes. A Canned Voice Message (CVM) Utility program 836 prepares ina form suitable for storage on the system disks 120 the digitized voicedata for the VMS canned voice messages.

80/30 Master Processor Online Programs

The Master Processor Online Program 808 runs in the master processor ofthe administrative subsystem 60 during online operation. Some of theseprograms are not limited to online use only (for example--the devicehandlers for the console CRT 104 and the line printer 108). A VMS OnlineInitializer program 838 performs a variety of initialization functionsthat are required to bring the system into an online state. Thesefunctions include initializing (or restoring) global system tables inmemory, and giving instructions for the other processors (the master andthe multiple call processors) to initialize themselves. A VMS CommandProcessor (COMSUP) program 840 provides all the functions required tosupport the VMS online command set. These commands are entered into thesystem via the console CRT 104. A Journal/Alarm Message Generatorprogram 842 is to create and format, at the request of other programs inthe system, journaling and alarm messages that are destined to bedisplayed on the system line printer 108. Journal messages, which arenormally no more than one or two lines in length, are used to create arunning log of "events" that occur during normal system operation. Alarmmessages are used to log the occurrence of "abnormal" conditions thatmay require action by the system operator. A Printer Spooler program 844"spools" the incoming requests for log messages to the system disk, andalso to subsequently "de-spool" the messages and print them on the lineprinter 108. This mechanism allows printed messages to be temporarilybuffered on disk while waiting for the line printer 108 to becomeavailable.

The CRT Control program 846 is a device handler that provides aninterface between the CRT 104 keyboard/display and any programrequesting I/O operations within the CRT 104. An LP Control program 848is a device handler that provides an interface between the line printer108 and any programs requesting output operations to the printer.

Report Generator Programs 850 prepare, in a form suitable for the lineprinter, statistical reports on various aspects of system operations.The following types of reports are included:

(1) A Port Usage Report 852 provides usage statistics for the voicecommunication ports.

(2) A Call Report 854 provides statistics related to the incoming andoutgoing calls that occurred during the report period.

(3) A Message Report 856 provides statistics related to new messagesreceived and messages delivered during the report period.

(4) A User Command Usage Report 858 provides usage statistics for theuse-frequency of the VMS 10 functions that may be invoked by users attheir telephones.

(5) A Disk Storage Report 859 provides information on utilization ofdisk storage, and "soft errors" that may have occurred on individualdisks.

80/30 Slave Processor Online Programs

The programs of the Slave Processor Online Programs 810 runs in theadministrative subsystem 60 during online operation. The functions ofmost of these programs can be summarized by saying that they performsupport operations that are requested by commands coming "upstream" fromprograms in the call processors 62A-62C.

A Message Router program 860 is informed of each occurrence of a newincoming message that has been received and stored in the system. It isresponsible for creating the Message Control Block on disk, and insuringthat the message is queued to each of its addresses. The program is alsoresponsible for "expanding" distribution codes that are used asaddresses.

A Message Dispatcher program 862 acts on requests coming up from thecall processors 62A-62C to provide messages for delivery. For eachrequest it will provide the address in disk storage 120 of the nextmessage to be delivered to a user. There is an existing connection withthis user for the purpose of delivering messages. After the message hasbeen delivered it will be dequeued. A Voice-Data Cell Allocator program864 allocates disk space for storing voice messages. Requests for spacecome "upstream" from programs in the call processors 62A-62C. TheAllocator responds to these requests by returning (to the requestingprograms) the addresses of the allocated disk storage.

A Message Storage Overwrite Protector program 866 Protects "old"undelivered voice messages from being overwritten. As the Allocatorprogram 864 continues to allocate disk storage space, the point willeventually be reached where some of this space must be re-used. It isthe responsibility of the overwrite protector program 866 to insure thatany undelivered messages in the space that is about to be re-used areprotected or moved. A Circuit Control program 868 is responsible foroverall control of the voice circuits. Information that comes upstreamfrom the call processors 62A-62C that reflects changes in circuit statusis handled by this program, as are status changes that result fromcommands by the system operator. A Call Scheduler program 870 isresponsible for scheduling and initiating outgoing calls to users thathave messages in queue awaiting delivery. Also included is theassignment of circuits for the outgoing calls.

An Inter-Processor Exchange Control program 872 is to pass informationfrom programs running in the master processor 808 to those in the slaveprocessor 810, and vice-versa. The external interface to this programlooks like that for the block-bus control program. Internally, the maindifference is that the data to be exchanged is passed through commonmemory that is addressable by both master and slave processors insteadof being transmitted across the block-bus. There are two complementarysections of this program. One runs in the master, and one in the slave.

80/30 Call Processor Online Programs

The Call Processor Online programs 812 run in the call processor 62A-62Cduring online operation. Most of the functions provided by theseprograms are concerned with implementing the VMS user functions (thosefunctions a user may invoke from his telephone).

A Transaction Timer Control program 874 is to manage the various"watchdog" timers that control the time limits applied to the variousVMS 10 user functions. A Circuit Control and Status program 876 isresponsible for overall control of the voice circuits attached to asingle circuit subsystem. It reports changes in the status of circuits"upstream" to the slave processor, and responds to explicit requests forcircuit state changes that come "downstream" from the slave processor. ACircuit Adapter control program 878 is a "device handler" that directlycontrols the hardware interface to a circuit module adapter. All I/Ooperations for the circuit modules and circuits are directed to thisprogram.

A Block-Bus Adapter Control program 880 is a device handler program thatdirectly controls the hardware interface to a block-bus adapter. Thepurpose of the block-bus, its hardware adapters (one in theadministrative subsystem 60, and one in each circuit subsystem), and itshandler program is to provide a path for communication between programsthat are running in the different subsystems. A Disk Adapter Controlprogram 882 directly controls the hardware interface to a disk adapter114 or 116. All requests for data transfer to/from the data storagesubsystem 64 are sent to this program. Notice in FIG. 1 that identicalcopies of this program run in the call processors and in the slaveprocessor of the administrative subsystem. A Call Processor Initializerprogram 884 provides all of the functions required to bring a CallProcessor into an online state after an initial program load.

A VMS User Function Processors program 886 provides all of the functionsrequired to communicate with a VMS user at his telephone, and executesthe VMS commands that are invoked by the user (by dialing digits). Thesefunction processors can be divided into five categories as follows:

(1) An Incoming Call Processor 888--controls the "answering" of incomingcalls to VMS from users.

(2) An Outgoing Call Processor 890 controls the dialing and connectionestablishment for outgoing calls to users.

(3) Delivery and Inquiry Processors 892 control the process ofdelivering voice messages to a user; either for the "normal" deliveryfunction (on an outgoing call), or the Inquiry function (on an incomingcall).

(4) A Deposit Processor 894 controls the process of receiving andstoring new voice messages from users.

(5) Miscellaneous SFC Processors 896 are processors for SpecialFunctions Codes other than those that are included in the Delivery andInquiry Processors.

VMS SYSTEM CONTROL AND DATA FLOW

FIGS. 23 and 24 show the control and data flow of the VMS 10 onlinesystem and software. Those programs shown in FIG. 22 that are used in anoffline mode only do not appear in FIGS. 23 and 24. The solid linebetween programs denote paths of control flow. The dashed lines denotepaths of data flow.

Call Processor Control and Data Flow

FIG. 23 shows the control and data flow for the programs that run in thecall processor 62A-62C. All of the programs which must communicate withthe voice circuit hardware do so via the Circuit Adapter Control Program878. It is the "device handler" program for a circuit adapter hardwareinterface 900. Interface 902 represents the communication between thisprogram and the circuit adapter hardware via a silo data structure 904in shared memory. At least two silos are actually required; one for"downstream" commands from the program to the circuit controllers (viathe circuit adapter), and one for status information coming "upstream"from the circuit controllers. Interface 906 represents hardware I/Ocommands issued by the control program directly to the circuit adapterinterface. This is normally required only when the circuit adapter isbeing initialized after an initial program load (IPL), or after a changein the state of a silo (i.e., from an "empty" to a "not empty" state).Interface 908 represents the flow of data to/from Circuit Adapter Tables910 and the control program 878 and hardware interface 900. These tablesare used for data that is related to commands going downstream or statuscoming upstream. There is a separate entry in these tables for eachvoice circuit attached to the circuit subsystem. In summary, commandsfrom the program 878 to the interface 900 pass through the downstreamsilo of silo structure 904. Status information from the interface to theprogram passes through the upstream silo of silo structure 904.Additional information related to the commands and status is depositedin and extracted from the adapter tables 910 by both the program and thehardware interface.

Circuit Adapter/Disk Adapter Interface

Interface 912 and 914 represent the information flow between the CircuitAdapter hardware interface 900 and a Disk Adapter hardware interface916. The Circuit Adapter control program 878 may issue read/writecommands directly to the Disk Adapter 76 or 78 (FIG. 4) and no relatedprocessing is required by programs running in the 80/30 call processor72 (FIG. 4). The Circuit Adapter program 878 accomplishes this bydepositing requests for disk I/O operations directly in the Disk Adapterdownstream silo of silo 917, thus bypassing the Disk Adapter ControlProgram 882. The disk I/O operations that may be requested by theCircuit Adapter are associated with writing/reading segments of voicemessages to/from disk. The data comprising these message segments istemporarily stored in voice data buffers 136 or 138 (FIG. 8) (in sharedmemory). These buffers are allocated from and released to a buffer poolthat is managed by both the Disk Adapter 114, 116 and the CircuitAdapter. The memory used for these buffers is located outside the 64Kaddress space of the Call Processor 72, and is therefore not addressableby this processor.

Disk Adapter Control Program/Hardware Interface

All programs residing in the 80/30 Call Processor 72 that must performdisk I/O do so by issuing requests to the Disk Adapter Control Program882 which, in turn, interfaces directly with the disk adapter hardwareinterface 916. This interface is implemented with at least one"downstream" silo and "upstream" silo (see interfaces 918 and 920).Requests for disk I/O operations are deposited by the control programinto the downstream silo, and status information (usually indicating I/Orequest completions) is inserted into the upstream silo by the diskadapters 114, 116. Interface 920 denotes hardware I/O operations(including interrupts) that pass directly between the control programand the hardware interface. These are normally used only to initializethe disk adapters 114, 116 and to signal a change in state of a silo(for example, from "empty" to "not empty").

Block-Bus Adapter Control Program/Hardware Interface

The communication of information between programs running in the CellProcessors 62A-62C (in Circuit Subsystems) and programs in theAdministrative Subsystem 60 is accomplished by passing this informationacross the block-transfer-bus (or "Block-Bus"). Application programsinterface with a block-bus adapter hardware interface 922 by issuingrequests to the Block-Bus Adapter Control Program 880, which, in turn,interfaces with the adapter hardware with a silo control mechansim 924(Interfaces 926 and 928). This mechanism is almost exactly the same asthat described above for the disk adapter, and it does not need to berepeated.

Application Program Interfaces to Block-Bus Control Program

Interface 930 represents requests originating in the Disk AdapterControl Program 882 for alarm messages to be printed on the line printer108, which will occur when disk errors are detected. Interface 932represents all of the communication paths between the VMS User FunctionProcessors 886 and the Slave Processor in the Administrative Subsystem60. These include:

(1) downstream commands to originate outgoing calls,

(2) upstream notification of answered incoming calls,

(3) upstream notification when a new voice message has been received(this information is processed by the Router Program 860 in the SlaveProcessor, which creates the Message Control Block [MCB] for the newmessage, and inserts entries in the queues for the addresses of themessage),

(4) downstream commands to deliver outgoing messages, and upstreamnotification of message delivery (this information is processed by theMessage Dispatcher Program 862 in the Slave Processor, which issuescommands for message delivery, and then de-queues messages after theyare delivered),

(5) miscellaneous upstream requests to Slave Processor programs 810 thatoriginate in the Special Function Code Processors 896. Interface 934consists of upstream requests from the Circuit Control and StatusProgram 876 that are reporting a status change in a circuit, anddownstream commands from the Slave Processor 810 that force a change inthe status of a circuit.

Interfaces With User Function Processors

Interface 936 represents any requests for disk I/O that originate in theVMS User Function Processors 886.

Interface 938 represents commands originating in the User FunctionProcessors 886 that are destined for individual voice circuits, andupstream status information that originates in the voice circuitcontrollers. Associated with this status information is data depositedthrough interface 940 by the Circuit Adapter Control Program 878 in theCircuit Tables 942.

Interface 944 represents control functions performed by the TransactionTimer Control Program 874. It consists primarily of requests to "awaken"the continuation of processing for a particular circuit when a "watchdogtimer" has expired.

Interface 948 represents control function flow between the User FunctionProcessors 886 and the Circuit Control and Status Program 876 that occuras a result of circuit status changes.

Interface 952 represents data flow between the User Function Processors886 and the Circuit Tables 942. These tables contain entries (an "entry"is a single circuit table) for all of the voice circuits controlled bythe Call Processors 62A-62C. Each circuit table, in turn, contains allof the information required for the Call Processors 62A-62C to controlthe circuit, and to execute the VMS functions during calls that use thecircuit. Note that several programs other than the User FunctionProcessors 886 must also access selected information in Circuit Tables942. These are the Circuit Adapter Control Program 878, the TransactionTimer Control Program 874 and the Circuit Control and Status Program876.

Master and Slave Processors Control and Data Flow

FIG. 24 shows the control and data flow for those programs residing inthe master and slave processors of the administrative subsystem 60.Although these two processors run asynchronously with respect to eachother, a part of their addressable memory space 954 is shared. Tableswhich must be accessed by programs in both processors reside in thiscommon memory space and include cell allocation tables 956, systemtables 958, circuit tables 942, user tables 960 and call schedulingtables 962.

Two programs residing in the slave processor that control hardwareinterfaces, the Disk Adapter Control Program 882 and the Block-BusControl Program 880, are essentially these same programs residing in theCall Processor of FIG. 23. These have already been discussed in thedescription of the control and data flow for the Call Processor, andwill not be discussed again here.

Interprocessor Exchange Control Program

The Interprocessor Exchange Control Program 872 provides a mechanism forthe transfer of information between programs running in the slaveprocessor and those running in the master processor. The externalinterface to this program is very similar to that for the Block-BusControl Program 880. The major internal difference is that, instead oftransferring the messages between programs via the block-bus, thetransfer is by way of common memory. The mechanism uses silos forinterprocessor synchronization; however, there is no hardware interfacelike the block-bus interface involved in the process.

Voice-Data Call Allocator and Message Overwrite Protector

The Voice-Data Call Allocator 864 services requests for allocation ofvoice-data storage cells that originate in the Call Processor 62A-62C.Using data in the Cell Allocation Tables 956, disk space is allocated,and the address of this space is returned to the requesting programs.When almost all of the voice-data cells on a particular disk have beenallocated, the address of this space is returned to the requestingprograms. When almost all of the voice-data cells on a particular diskhave been allocated, the Message Overwrite Protector 866 is activated.This program checks for the presence of any cells still in use thatreside in the storage areas that are about to be re-used or allocatedagain. Any such cells are "protected" by moving them. The requests fordisk I/O are made by the Overwrite Protector 866 for the purpose ofmoving voice-data cells to the Disk Adaptor Program 882.

Message Router

When a new message has been received and stored on disk, the appropriateCall Processor sends a request upstream to the Message Router program860. This program performs two major functions. First, it creates theMessage Control Block (MCB) from information contained in the upstreamrequest. The MCB contains most of the bookkeeping and controlinformation required for subsequent processing of the message. Thesecond function performed by the Message Router Program 860 is todeposit entries in the output queues for the addresses of the message.

Message Dispatcher

The Message Dispatcher 862 provides Call Processor informationconcerning the pending delivery of an outgoing message. When thedelivery process on a call has progressed to the point where delivery ofan outgoing message is to begin, the Message Dispatcher 862 is notifiedby the appropriate Call Processor 62A-62C through Block-Bus ControlProgram 880. The Message Dispatcher 862 selects a message from a queueand returns information concerning the identity and location of themessage to the Call Processor 62A-62C. The Dispatcher 862 always selectsa message that is at the top (beginning) of a particular queue to bedelivered next. If there is more than one queue to be considered (somemessage recipients may have more than one FIFO queue), then theselection of the queue is made on a priority basis. The Call Processor62A-62C will again notify the Dispatcher 862 after it has successfullydelivered the selected message. The Dispatcher 862 will respond bydequeueing this message, and selecting another message for delivery. Ifthere are no additional messages awaiting delivery, then the Dispatcher862 informs the Call Processor 62A-62C that the queues for thisaddressee are empty.

Circuit Control

The Circuit Control and Status Program 876 communicate with one of theCall Processors 62A-62C via Block-bus 880. Communication across thisinterface occurs for the following types of events:

(1) Circuit Control is notified when an autonomous change in the statusof a circuit occurs. The new state is duly recorded in the CircuitTables 942, and if the new state is an "abnormal" one (such as circuitout of service), a request is sent to the Journal/Alarm Program 842 togenerate an appropriate alarm message.

(2) Circuit Control is also notified when a circuit autonomously goesoff-hook (an incoming call is answered), and when a disconnect occurs onan existing call.

(3) Circuit Control interfaces with the VMS Command Processor Program840 (in the master processor) for operator commands which dictatechanges in the state of a voice circuit.

In these cases Circuit Control will update the appropriate items in theSystem Tables 958 and Circuit Tables 942, and, if necessary, theappropriate commands downstream to the affected Call Processor 62A-62C.

Call Scheduler

The Call Scheduler 870 is responsible for the scheduling of outgoingcalls to message addresses. It uses information recorded in the UserTables 960 and Call Scheduling Tables 962 to decide when to initiate acall. The actual request to initiate a call is sent to the CircuitControl and Status program 876.

Journal/Alarm Generator

The Journal/Alarm Generator 842 receives requests for specific journalor alarm messages that are to be "logged" on the system line printer108. It formats the messages, and then passes them to the Printer SpoolProgram 844 in the master processor.

Line Printer Control and Printer Spool Programs

When the VMS system 10 is operating online, all requests for theprinting of information on the line printer 108 are sent to the PrinterSpool Program. These requests originate in the Journal/Alarm Generator842 and the Report Generator Programs 850. The Spool Program 844"buffers" these requests by writing them on the disks. It then schedulesthe print requests in an orderly manner to the Line Printer ControlProgram 848. This program, in turn, directly controls the line printerhardware interface 964.

Report Generator Programs

The requests for the different types of reports originate directly, orindirectly, in the VMS Command Processor Program 840. The directrequests are caused by VMS commands that explicitly request thegeneration of a specific report. The indirect requests are caused by VMScommands that set the time-of-day and time intervals for generation ofspecific reports. These reports are then created on a time-periodicbasis. Most of the information required for creating a report iscontained in the System Tables 958 and Circuit Tables 942.

VMS Command Processor

This program receives system operator commands from the CRT ControlProgram 846, performs the function requested by the command, and returnsa response to the operator. Some of these command functions have alreadybeen discussed, such as report generation requests and circuit controlrequests. Other commands are requests for various types of statusinformation. The Command Processor 840 extracts this information fromthe System Tables 958 and Circuit Tables 942 and the User Tables 960.

Console CRT Control Program

This is a "device handler" program which directly controls the CRThardware interface 966. It acepts read and write requests for the CRT104.

VMS Online Initializer

The VMS Online Initializer program 838 performs a variety of functionsthat are required to bring the system into an online state. To do thisit must access information from the following tables shown in sharedmemory 954:

(1) the Cell Allocation Table 956,

(2) the System Tables 958 and Circuit Tables 942,

(3) the User Tables 960, and

(4) the Call Scheduling Tables 962.

At least a portion of the information in each of the above tables, theportion accessed by the Initializer, is maintained in non-volatilememory so that it is not destroyed when system power is removed.

Referring now to FIGS. 25a-25c, there is illustrated a schematic diagramof a portion of the Codec illustrated in FIG. 9. The schematic diagramrefers to the portion of the Codec that converts the analog to thedigital and the digital to the analog. The schematic diagrams of FIG. 25also include the tone receiver 164 and the tone generator 166 of FIG. 9that convert a digital signal to a DTMF digit and also convert a DTMFdigit back to a digital word. The VCA interface logic 156 of FIG. 9 nowoutputs a tip and ring signal which is input to the circuit of FIG. 25aon the connectors labeled CT1 CT and CR1 CR. This is for two-wiretransmission only. The situation where four-wire transmission is allowedby the telephone company will be described hereinbelow.

The tip and ring signals are input to a signal conditioning circuit 1000which is comprised of operational amplifiers 1002, 1004 and 1106(hereinafter referred to as op amps). Op amp 1002 is configured as aunity gain noninverting amplifier by connecting the negative inputthereof to the output thereof. The op amp 1004 is configured as aninverting amplifier. The components attached to the input terminals andthe output terminal of op amp 1004 have values determined by the desiredgain. These values can be determined from design equations that arefound in the Linear Applications Handbook from National SemiconductorsCorp. In the present application, the gain of the op amp 1004 is set forunity gain. It should be understood that although a unity gain amplifierhas been utilized for the amplifier 1002, a design for an op amp havinga gain larger than one can be implemented by inserting a noninvertinggain operational amplifier circuit in place of the unity gain amplifier.

The output of op amp 1004 is connected to the CT1, CT input line by aresistor 1008. The output of op amp 1002 is connected to the input lineCR1, CR through a resistor 1010. The resistors 1008 and 1010 are bufferresistors and provide a certain degree of isolation between the outputsof the op amps 1002 and 1004 and the lines CR1, CR and CT1, CT. In theconfiguration shown, op amps 1002 and 1004, both having unity gain, forma complementary amplifier. This complementary amplifier is used to drivethe telephone line which is connected to the lines CT1, CT and CR1, CR.The impedence of the telephone line is 600 ohms.

Op amp 1006 is configured as a differential amplifier having thepositive input thereof connected through a resistor 1012 to the CT1, CTterminal and the positive input thereof connected through a resistor1014 to the CR1, CR terminal. The gain of the differential amplifier isset equal to unity for the present application and it functions as areceiver to receive signals from the telephone line. A resistor 1016 isconnected between the terminal CT1, CT and CR1, CR. The output of the opamp 1004 is connected through a resistor 1020 to the positive input ofthe op amp 1006. The resistor 1020 acts as a summing resistor to allowthe output of the op amp 1004 to sum with the difference signal detectedby the op amp 1006. The resistor 1020 in effect subtracts or cancels thetwo signals at the positive input of the op amp 1006. The purpose of theresistor 1020 is to reduce or eliminate transmitted signals output by opamps 1002 and 1004 from appearing on the output of op amp 1006.

A jumper 1022 and a jumper 1024 are connected between the resistors 1010and 1014 and the resistors 1008 and 1012, respectively. The purpose ofthe jumpers 1022 and 1024 is to accommodate four-wire telephone lines.The four-wire telephone lines makes provisions for transmission on twoof the four wires and reception on te remaining two wires therebyproviding increased isolation. In a four-wire system, the transmissionoccurs on the terminal CT1, CT and CR1, CR and reception occurs on theinput terminals CT and CR which are connected to the opposite sides ofthe jumpers 1022 and 1024 from the terminals CT1, CT and CR1, CR.

In applications where a particular system requires the presence ofhigher gain receiving amplifiers or higher gain transmitting amplifiers,the signal conditioner 1000 is constructed such that it can be replacedto accommodate a particular system. This allows the circuit a higherdegree of flexibility from unit to unit which can be customized to acustomer's specification.

The output of the op amp 1006 is connected to one input of a dual analoggate 1026. The analog gate 1026 is of the type 7G201 manufactured bySiliconix, Inc. An inverter 1028 has the input thereof connected to asignal line labeled LOOP BACK and the output thereof is connected to oneof the control inputs of the analog gate 1026 and controls theconnection of the output of the op amp 1006 to the output of the analoggate 1026. A pullup resistor 1030 is connected between the input of theinverter 1028 and the positive supply voltage. An inverter 1032 has theoutput thereof connected to the other control input of the analog gate1026 and input thereof connected to the output of the inverter 1028. Thetwo outputs of the dual analog gate 1026 are connected to a node 1034and the inverters 1028 and 1032 are operable to selectively connect oneof the inputs of the dual analog gate 1026 to the node 1034. The otherinput of the analog gate 1026 is connected to a node 1036.

A DTMF receiver 1038 and a DTMF receiver 1040 have the input thereofconnected to the node 1034. The DTMF receivers are operable to receivethe received analog signal and, if DTMF signals are present,discriminate the signals into logic signals corresponding to the varioustones. The receivers 1038 and 1040 output a separate digit for each ofeight discrete tones. The eight tones are 697 Hz, 770 Hz, 852 Hz, 941Hz, 1209 Hz, 1336 Hz, 1477 Hz, and 1633 Hz. The receivers 1038 and 1040are of the type 550 manufactured by Frequency Devices Inc. The presenceof the four lower frequencies are operable to individually activate oneof the four outputs of the receiver 1038. The four outputs of thereceiver 1038 are inverted by a group of inverters 1042 to provide thesignals TL0, TL1, TL2, and TL3, which correspond to increasingfrequencies. The four digital outputs of the receiver 1040 areindividual activated by the four higher frequencies and these outputsare inverted by a group of four inverters 1043 to provide the outputsignals TH0, TH1, TH2, and TH3. The output TL0-TL3 are the low tonedigital outputs of the DTMF and the outputs TH0-TH3 are the high tonedigital outputs. The outputs provide a digital signal that is input tothe circuit of FIG. 8.

A programmable gain amplifier 1044 is comprised of op amps 1046, 1048,1050 and 1052. Each of the op amps 1046-1052 is configured as aninverting amplifier having a gain specified by the components attachedthereto. The gain of each of the op amp circuits is controlled by aseries of four dual analog gates 1054, 1056, 1058, and 1060 similar intype to the analog gate 1026. Each of the dual analog gates 1054-1060have both outputs connected together and each of the outputs areconnected to the negative input of each of the op amps 1046-1052,respectively. The positive input of the op amp 1048 is connected toground through a resistor 1064. The op amp 1050 has the positive inputthereof connected to ground through a resistor 1066. The op amp 1052 hasthe positive input thereof connected to ground through a resistor 1068.The output of the op amp 1046 is connected to the negative input thereofthrough a series resistor 1070 and connected to the first and secondinputs of the dual analog gate 1056 through resistors 1072 and 1074,respectively. The op amp 1048 has the output connected to the negativeinput thereof through a series resistor 1076 and connected to bothinputs of the dual analog gate 1058 through series resistors 1078 and1080, respectively. The op amp 1050 has the output thereof connected tothe negative input thereof through a series resistor 1082 and to theinput of a capacitor 1084. The other end of the capacitor 1084 isconnected to both inputs of the dual analog gate 1060 through seriesresistor 1086 and 1088, respectively.

The op amp 1052 has the output thereof connected to the negative inputthereof through a series resistor 1094. A zener diode 1093 has thecathode thereof connected to the cathode of a zener diode 1095 and theanode thereof connected to the input of the filter 1092. The anode ofthe diode 1095 is connected to ground. Diodes 1093 and 1095 provide alimiting function for the input of the filter 1092. The filter 1092reduces some of the high frequency components to allow conversion todigital signals. It is of the type 28-1637 manufactured by Alladdin. Thenode 1034 is connected to one side of a capacitor 1096 and the other endof the capacitor is connected to both inputs of the dual analog gatethrough series resistors 1098 and 1100, respectively.

A digital signal G0 is connected to the control inputs of the dualanalog gate 1054 by a serially connected pair of inverters 1102. Theserially connected inverters 1102 provide both the inverted andnoninverted forms of the signal G0. This allows the signal G0 to controlthe operation of the digital analog gate 1054. In this manner, theanalog signal passed through the capacitor 1096 is input to the op amp1046 through a selected one of the resistors 1098 and 1100 dependingupon the state of the signal G0. A digital signal G2 is connected to thecontrol inputs of the analog gate 1056 by a serially connected pair ofinverters 1104. A digital signal G3 is connected to the control inputsof the analog gate 1058 by a pair of serially connected inverters 1106.A digital signal G1 is connected to the control inputs of the analoggate 1060 through a pair of serially connected inverters 1108. Thedigital signals G1-G3 control the operation of the analog gates1056-1060 in a manner similar to the control of the analog gate 1054 bythe signal G0.

The operation of each of the op amps 1046-1052 and the gain thereof willbe described with reference to only the op amp 1046. The op amp 1046 isconnected as an inverting amplifier with the resistor 1070 serving asthe feedback resistor and the resistors 1062 and one of the resistors1098 and 1100 serving as the gain select resistors. The analog gate 1054selects which of the resistors 1098 or 1100 are to be part of the gaincircuit. The values of these resistors can be selected according todesign equations that can be found in the Linear Applications Handbookpublished by National Semiconductor Corporation. Depending upon thestate of the signal G0, resistor 1098 or resistor 1100 can beselectively connected to the negative input of the op amp 1046 tocomprise one leg of the gain circuit. This provides two degrees offreedom in choosing the gain of the amplifier. The resistor 1070 has avalue equal to the value of one of the resistors 1100 and 1098 such thata gain can be set to unity. Therefore, the gain of the amplifier circuitcan be either unity or higher depending upon the value of the remainingresistor of the pair connected to the input of the analog gate 1054.Each of the op amp circuits 1048, 1050 and 1052 operate in a similarmanner, thereby providing 16 levels of gain depending upon the signalsG0-G3. In the present application, the gain range is from 0 to 60 Db inincrements of approximately 4 Db.

The output of the filter 1092 is connected to the positive input of acomparator 1110 through a series capacitor 1112. The positive input ofthe comparator 1110 is connected to the positive voltage supply througha resistor 1114. The negative input of the comparator 1110 is connectedto the output of a digital to analog converter (D/A) 1116. The output ofthe comparator 1110 is connected to the positive voltage supply througha pullup resistor 1118. The comparator 1110 is of the type LM311manufactured by National Semiconductor Corp.

The D/A converter 1116 is a general purpose 10 bit device which isoperable to receive 10 bits of information from the Delta modulator 150of FIG. 9 and convert this digital information to analog signals. Thedigital word is input on the line labeled D0-D9 and inverted by a seriesof ten inverters 1120. The inverters 1120 each have the input thereofconnected to one of the data lines D0-D9 and the outputs thereofconnected to one of the ten inputs of the D/A converter 1116. Each ofthe inverters 1120 has the inputs thereof connected to one of aplurality of resistors in a resistor bank 1122, each of the resistorshaving the other end attached to the positive voltage supply. Theresistors 1122 perform a pullup function for the input of the inverter1120. The D/A converter 1116 outputs an audio signal in response to adigital signal input from the bus on the data lines D0-D9 and this audiosignal is input to the negative input of the comparator 1110. Thecomparator 1110 compares the output of the D/A converter 1116 and theoutput of the filter 1092 to output a signal DATA OUT.

When the signal is being received off of the telephone line and ananalog signal is output from the filter 1092 having an amplitudedetermined by the gain of the programmable gain amplifier 1044, thesystem generates another signal on the data lines D0-D9 which is outputby the D/A converter 1116 for comparison. This is a correction signalthat is generated in response to a signal that the system thinks ispresent. This drives the digital portion of the Delta modulator 150 ofFIG. 9 to adjust its digital value to the converter 1116 for the nextsample. It should be understood that when the analog to digitalconversion is not performed on the circuit shown in FIGS. 25A-C, ananalog signal must be sampled in order to convert it to a digitalrepresentation. The compensation is performed for each sample tocompensate for the quality of the sound. The rate of this sampling ismany times faster than the frequencies present in voice information.

The output of the filter 1092 is also connected through a resistor 1124to the input of a peak detector 1126. The peak detector 1126 utilizes ageneral purpose op amp to perform the detection by connecting the outputto the negative input thereof through a series connected diode 1125 andresistor 1127 and tapping the output off of the negative input thereof.A five-bit level detector IC 1128 has the input thereof connected to theoutput of the peak detector 1126 and each of the five outputs thereofconnected to the input of an individual one of a series of five ANDgates 1130 configured as buffers. Each of the outputs of the AND gates1130 are labeled L0, L1, L2, L3, and L4 and represent various levels forthe audio signal. A series of pullup resistors 1132 connect each of thefive outputs of the level detector 1128 to the positive voltage supplythrough a single resistor. The output of the five bit level detectoroutputs a digital bit on each output in a sequential fashion dependentupon the input analog level such that the lowest level corresponds tothe signal L0 and the highest level corresponds to the signal L4. The IC1128 is of the type TL489 manufactured by Texas Instruments Inc. An ANDgate 1134 configured as a buffer has the input thereof connected to L0from the level detector 1128, an identically configured AND gate 1136has the input thereof connected to L2 from the level detector 1128 andan identically configured AND gate 1138 has the input thereof connectedto L4 from the level detector 1128. Each of the AND gates 1134-1138 hasthe outputs thereof connected to the cathode of a light-emitting diode(LED) 1140, 1142, 1144, respectively. Each of the LEDs 1140-1144 isconnected to the positive voltage supply through a pullup resistor 1146,1148, and 1150, respectively. LED 1144 indicates that the audio level islow, LED 1142 indicates that the audio level is medium, and the LED 1140indicates that the audio level is high. The LED's are located physicallyon the front panel of the system so as to inform an operator of thecondition of the audio level.

A tone generator 1152 receives digital information from the busdescribed above and generates an output DTMF signal on an output node1154. The tone geenerator 1152 is of the type MK5089 manufactured byMostek, Incorporated. The tone generator 1152 has the capability ofproducing eight different tones. These tones can be produced one at atime or two at a time. There are a series of high-frequency tones andlow-frequency tones, the frequency of which were described hereinabovewith reference to the receivers 1038 and 1040. The digital signals forthe high-frequency tones are received on the data lines R0, R1, R2, andR3. The data lines C0-C3 and R0-R3 are buffered by a series of AND gates1155 that have the individual inputs thereof connected to the respectivedata line and the outputs thereof connected to a correspondingindividual input of the tone generator 1152. The frequency of the toneson the tone generator 1152 are controlled by a crystal 1156.

The output node 1154 is connected through a capacitor 1158 and through aseries resistor 1160 to the negative input of an op amp 1162. The op amp1162 is part of the signal conditioning circuit 1000, as indicated bythe dashed line. A resistor 1164 is connected between the output and thenegative input of the op amp 1162. A resistor 1166 is connected betweenthe positive input of the op amp 1162 and ground. The resistors 1160,1164 and 1166 in conjunction with the op amp 1162 form a unity gaininverting amplifier. A resistor 1168 is connected between the output ofan analog gate 1170 and the negative input of the op amp 1162. Theresistor 1168 in conjunction with the remaining resistors 1164 and 1166results in a higher gain for the amplifier than that using the resistor1160. The overall amplifier circuit utilizing the op amp 1162 is asumming amplifier, with resistors 1160 and 1168 serving as the summingresistors which sum the output of the analog gate 1170 and the tonegenerator 1152. The input to the analog gate 1170 is connected to theoutput of the D/A converter 1116 through a capacitor 1172. A resistor1174 is connected between the input of the analog gate 1170 and ground.An inverter 1176 has the input thereof connected to a DECODE/ENCODE lineand the output thereof connected to the control input of the analog gate1170. The signal on the DECODE/ENCODE line is operable to sum the outputof the D/A converter 1116 with the output of the generator 1152. The opamp 1162 performs a mixing function on the two outputs.

The output of the op amp 1162 is connected through a resistor 1178 to afilter 1180. The filter 1180 is similar to the filter 1092 and functionsto filter out high frequency components of the D/A converter 1116 andthe tone generator 1152. The output of the filter 1180 is connected tothe input of an analog gate 1182 at the node 1036. The control input ofthe analog gate 1182 is connected to the output of the inverter 1028 andis controlled by the LOOP BACK signal.

In the encode mode, the analog gate 1170 connects the output of the D/Aconverter 1116 through the op amp 1162 on the signal conditioning board1000 to the input of the analog gate 1182. When the analog gate 1182 isactivated, the signals from the D/A converter 1116 are transmitted tothe input of the op amps 1004 and 1002 along with the output of the tonegenerator 1152 and from there to the telephone line. In the decode mode,information from the D/A convertor is not mixed with the output of thetone generator 1152.

The analog gates 1026 and 1182 are operable to respond to the LOOP BACKsignal to remove signals internal to the analog board from the telephonelines for purposes such as testing. When the LOOP BACK function isactivated, the analog gate 1182 is deactivated to prevent signals frominputting to the signal conditioning circuit 1000. The dual analog gate1026 has the analog gate connecting the output of the signalconditioning circuit 1000 to the programmable gain amplifier 1044deactivated and the remaining gate therein activated to connect theoutput of the filter 1180 to the programmable gain amplifier 1044. Thiseffectively connects the output of the op amp 1162 to the programmablegain amplifier 1044 which comprises the mixed signals from the tonegenerator 1152 and the D/A converter 1116.

An inverter 1184 has the input thereof connected to the output of theinverter 1176 and the output thereof connected to the cathode of an LED1186 to provide a buffer for driving the LED 1186. The anode of the LED1186 is connected to the positive voltage supply through a resistor1188. The DECODE/ENCODE signal, in addition to controlling the gateinput of the analog gate 1170, also drives the LED 1186 to indicate onthe front panel if the system is in the encode mode which is the modewherein a message is recorded. An inverter 1190 has the input thereofconnected to the output of the inverter 1028 and the output thereofconnected to the cathode of an LED 1192. The anode of the LED 1192 isconnected through a resistor 1194 to the positive voltage supply. TheLED 1192 indicates when the LOOP BACK signal is present.

An LED 1196 has the anode thereof connected to the positive voltagesupply through a series resistor 1198 and the cathode thereof connectedto the output of an inverter 1200. The LED 1196 indicates the select infunction on the front panel of the system. The input of the inverter1200 is also connected to the input of an inverter 1202 that outputs theSUPV IN signal. The input of the inverters 1200 and 1202 are connectedto either the input or the output of an inverter 1204 by selectivelyconnecting one of two jumpers 1206 and 1208, as indicated by the dashedlines. The input of the inverter 1204 is connected to the collector of atransistor 1210, the emitter of which is connected to ground. Thecollector of the transistor 1210 is connected to the positive voltagesupply through a resistor 1212 and the base of the transistor 1210 isalso connected to the positive voltage supply through a resistor 1214. Acontrol input CBS1, CTE, which is derived from the VCA 16, is input tothe anode of a diode 1216, the cathode of which is connected to the baseof the transistor 1210 through a series resistor 1218. The cathode ofthe diode 1216 is also connected to the negative voltage supply througha resistor 1220. The diode 1216 and the transistor 1210 with itsassociated components convert the signal input to drive the variousinverters and logic that is normally comprised of TTL logic. Thepositive voltage supply is normally +5 volts for this type of logic. Thejumpers 1206 and 1208 allow for positive or negative signalling to theinput of the inverters 1200 and 1202.

Referring to FIG. 25b, a circuit 1222 converts a negative voltagesignaling to a positive voltage signaling similar to the conversionafforded by the transistor 1210, the diode 1216 and the resistors 1212,1214, 1218, and 1220. The signal input to the circuit 1222 is labeled C1and is derived from the VCA board 16 and indicates when the VCA 16detects a ring signal. The output of the circuit 1222 is connected tothe input of an inverter 1224 and a series of jumpers 1226 are utilizedto connect either the input of the inverter 1224 or the output of theinverter 1224 to the input of an inverter 1228. The output of theinverter 1228 is connected to the cathode of an LED 1230 and the anodeof the LED 1230 is connected to the positive voltage supply through aresistor 1232. The LED 1230 indicates the presence of a ring signal andis labeled RING. The jumpers 1126 are operable to connect the detectedRING signal to the input of the inverter 1204 to provide the noninvertedsignal.

A switch 1234 is operable to generate an alarm busy signal ALB. It isalso used for maintenance mode operations. The switch 1234 in oneposition puts on an ALB signal and in the other position puts out theinverted ALB signal. This signal is input to the VCA 16 and forces aBUSY condition so that the line is busied, it also sends a signal to thecircuit microboard of FIG. 8 which enables an operator to simulate anincoming call and do on-board testing.

Referring to FIG. 25C, a transient suppressor diode 1236 has the cathodethereof connected to the input line labled CG and the anode thereofconnected to the input line labeled CS, CTM. A PNP transistor 1238 hasthe emitter thereof connected to the cathode of the diode 1236 and thecollector thereof connected to the anode of the diode 1236. A resistor1240 is connected between the emitter and the base of the transistor1238. A diode 1242 has the anode thereof connected to the base and thecathode thereof connected to the collector of a PNP transistor 1244. Thecollector of the transistor 1244 is connected to the negative voltagesupply through a resistor 1246 and the emitter thereof is connected tothe positive voltage supply. A resistor 1248 connects the base of thetransistor 1244 to a node 1250.

A transistor 1252 has the collector thereof connected to a negativevoltage supply -V' through a resistor 1256. The base of the transistor1252 is connected to -V' through a resistor 1258 and the anode of thediode is also connected to -V'. A PNP transistor 1260 has the emitterthereof connected to the positive voltage supply, the collector thereofconnected to the base of the transistor 1252 through a resistor 1262 andthe base thereof connected to the node 1250 through a resistor 1264. Thetransistors 1238 and 1244 and the diode 1242 form a circuit thatconverts positive voltage supply signaling that is output by TTL logicto a signaling voltage in the range of -24 volts. The transistors 1252and 1260 with their associated circuitry provide a source for the signalto the -V' voltage level.

A signal input line labelled SUPV OUT is connected to the input of aninverter 1266. A resistor 1284 has one end thereof connected to theinput of the inverter 1266 and the other end thereof connected to thepositive voltage supply to provide a pullup function. The output of theinverter is input to the input of an inverter 1268 and one end of acapacitor 1270. The other end of the capacitor 1270 is connected to theground. The output of the inverter 1268 is connected to the input of aninverter 1272. The output of the inverter 1272 is connected to thecathode of an LED 1274 and the anode thereof is connected to thepositive voltage supply through a resistor 1276. The LED 1274 gives anindication of the SELECT OUT function that is on the front panel.Resistors 1278 and 1280 connect the outputs of the inverters 1266 and1268 to the positive voltage supply, respectively. A pair of jumpers1282 allow for selection of the inverted or noninverted function forinput to the base of the transistor 1244 for conversion to -24 Vsignaling.

Referring now to FIGS. 26a-26h there is shown a schematic illustrationof the port driver system 92 of FIG. 8, commonly referred to as theCircuit Microboard. The circuit microboard is interfaced to the expander94 through the bus interface logic 134 to receive signals from the bus.Each of the circuit microboards is coded such that they can fit into anyof the given slots that are inherent to the bus interface logic 134. Byapplying the proper code to the expander 94 from the bus, one of theplurality of circuit microboards can be selected for interfacetherewith.

Referring further to FIGS. 26a-26h, the addresses for the circuitmicroboards are input on the lines marked ADRB, ADRC, ADRD, ADRE, andADRF. Each address is unique for a particular microboard. A jumper board1300 has eight input lines that are connected to the connectors labeledINT0, INT1, INT2, INT3, INT4, INT5, INT6, and INT7. Internal jumpers areplaced between the connector on the input side and one of the outputports, as shown by the dashed lines therebetween. The first five linesINT0-INT4 and the signals on these five lines are utilized to encode aparticular board. Each of the five lines INT0-INT4 are selectivelyconnected to ground elsewhere in the system (not shown) to provide aunique code for a particular circuit microboard. A resistor bank 1304has an additional resistor having one end connected to the positivevoltage supply and the other end connected to the output of thecomparator 1302 which is also the output of all five exclusive OR gates.When one of the inputs INT0-INT4 is not connected to ground, thecorresponding resistor in the resistor bank 1304 acts as a pull upresistor to set the logic state thereof to "high". The output of thisjumper board 1300 is compared to the address code input on linesADRB-ADRF. The digital signal on each of the signal lines ADRB-ADRF iscompared to a corresponding bit of data INT0-INT4. The output of thejumper board 1300 is applied to a comparator circuit 1302 that iscomprised of five open collector exclusive OR gates. Each of the databits input on the lines ADRB-ADRF is input to one input of one of theexclusive OR gates in comparator 1302 and a corresponding one of theoutputs from the jumper board 1300 is also input to each of theexclusive OR gate in the comparator 1302. The output line of thecomparator 1302 is labeled BD SEL and this line is activated when a codedetected on the bus matches the particular board coded on the linesINT0-INT4.

A demultiplexer 1306 has the A, B and C inputs thereof connected to theoutputs of inverters 1309, 1310 and 1312, respectively. The inputs ofthe inverters 1308-1312 are connected to the address lines ADR8, ADR9,and ADRA, respectively. The demultiplex circuit 1306 has a total ofeight output lines that correspond to the three-bit address word on theinput thereof. The demultiplex circuit 1306 outputs the DMA write(DMAWR), DMA read (DMARD), command write (CMDW), read status registerand reset status bit (STATR) and read status register without resettingstatus bit (STAT). The last bit output is a signal RESETA to provide asignal to reset the board. By inputting the correct 3-bit address on thelines ADR8-ADRA, a desired function can be selected.

Although the address lines ADR8-ADRA provide the three-bit word thatallows the bus to convey to the circuit microboard the desired functionsthat the board is to perform, it is still necessary to have the BD SELenable signal to select the desired board and enable the demultiplexcircuit 1306. With the use of the comparator circuit 1302 and thesignals input thereto, multiplexing of the bus is enhanced in that boththe function and the particular board codes are placed onto the bus,and, when a particular board is selected, this particular board performsthe required functions. This allows a plurality of boards (dependingupon the allocated address bits) to be utilized to perform the variousfunctions individually.

The CMDW, STATR, and STAT signals are input to a three-input NOR gate1308. The output of the NOR gate 1308 is input to an inverter 1310 theoutput of which provides the BUS 1 SEL signal. The use of the BUS 1 SELsignal provides a further multiplexing function that will be describedhereinbelow.

The bus data is input on lines DAT0, DAT1, DAT2, DAT3, DAT4, DAT5, DAT6,and DAT7. The first four bits of data, DAT0-DAT3, are input tomultiplexing circuits 1313 and 1314. The multiplexing circuits 1313-1318have tri-state outputs that allow a particular port to output bothstates of binary data or to "float", that is, the output isopen-circuited. In addition, both inputs can be connected to make thembi-directional. The multiplexing circuits are of the type 8226manufactured by INTEL. The BUS 1 SEL is input to the multiplexers 1313and 1314 provides a chip select signal thereto. The chip select signalactivates the particular pair of multiplexers to output binary data. ABUS 2 SEL signal is input to the chip select input of the multiplexers1314 and 1318 to provide the chip select signal thereto. The output ofthe multiplexer 1313 has four inputs thereof connected to the STAT0,STAT1, STAT2, and STAT3 signal lines, and the multiplexer 1316 has itsfour inputs connected to the STAT4, STAT5, STAT6, and STAT7 signallines, which are all part of the internal status signals. The fouroutputs of the multiplexer 1313 are connected to the CMD0, CMD1, CMD2,and CMD3 signal lines and the four outputs of the multiplexer 1316 areconnected to the CMD4, CMD5, CMD6 and CMD7 lines which are all part ofthe command internal bus. The multiplexer 1314 has four outputs and fourinputs that are connected to an internal address bus 1320 and arelabeled AD0, AD1, AD2, and AD3. The multiplexer 1318 has four outputsand four inputs connected to the address data bus 1320 and are labeledAD4, AD5, AD6, and AD7. The address/data bus 1320 carries both addressand data information.

The output of the multiplexers 1313 and 1316 or 1314 and 1318 that isselected is determined by the signal on either the BUS 1 SEL chip selectline or the BUS 2 SEL chip select line. If the BUS 1 SEL chip selectsignal is activated which activates the multiplexers 1313 and 1316, thebinary signal on the IORC.1 line controls which direction (in/out) thatthe data signals DAT0-DAT7 are to be "steered". For example, in onestate of the IORC.1 signal, all of the data is directed from theSTAT0-STAT7 inputs and in the other state, all of the data is directedtoward the CMD0-CMD7 outputs. When the BUS 1 SEL signal is notactivated, the outputs of the multiplexers 1313 and 1316 are floating.The multiplexers 1313-1318 allow the lines DAT0-DAT7 to be connected toeither the status lines, the command lines or the address/data bus 1320.The inputs/outputs of the multiplexers 1313 and 1316 are connected toeither the STAT0-STAT7 outputs or the CMD0-CMD7 inputs. The IC 1322provides the command/status register interface in addition to themodulator clock function. It is also connected to the system clock(CLK), system reset (RESET), CMDW signal, STATR signal, write (WR), read(RD) and the IO/M signal and also provides 256 bytes of RAM.

A NOR gate 1324 has one input thereof connected to the RD signal and theother input thereof connected to the WR signal. A NOR gate NAND has oneinput thereof connected to the DMA acknowledge signal for channel 0(DACKO) and the other input thereof connected to the DMA acknowledgesignal for channel 1 (DACK1). A NAND gate 1328 has one input thereofconnected to the output of the NOR gate 1324 and the other input thereofconnected to the output of the NOR gate 1326. The output of the NANDgate 1328 provides the BUS 2 SEL signal for controlling the chip selectinput of the multiplexers 1314 and 1318. The gates 1324-1328 thereforecomprise the circuitry that controls the multiplexers 1314 and 1318.

A central processing unit (CPU) 1330 controls the operation of thecircuit microboard. The CPU 1330 is of the type 8085 manufactured byINTEL Corporation. The CPU 1330 is connected to the internal bus 1320through connecting lines labelled AD0-AD7. An internal address bus 1332is connected to the CPU 1330 by the signals A8, A9, AA, AB, AC, AD, AE,and AF. A crystal 1334 is connected to the CPU 1330 to provide areference for the internal clock thereof. A clock signal (CLK) is outputby the CPU 1330 to the input of an inverter 1336. The output of theinverter is connected to the input of an inverter 1338. The inverter1336 provides a CLK signal and the inverter 1338 provides the CLK signalas a buffer output. The CPU 1330 performs the primary control of thecircuit microboard and the DMA controller 1422 aids the CPU 1330 byperforming slave functions. This allows for a more efficient allocationof CPU time. A latch circuit 1340 has inputs connected to the internalbus 1320 and labeled AD0-AD7 and outputs connected to the internal bus1332 labeled A0-A7. The latch 1340 is operable to receive informationfrom the internal bus 1320 and transfer this information to the internalbus 1332 on address lines A0-A7. An AEN signal enables the latch 1340 todemultiplex the address from the address/data bus 1320.

When the master Universal Control Board on the bus generates a commanddesiring to do an I/O read or an I/O write, the master Universal ControlBoard waits for an acknowledge signal before generating another command.The purpose for this procedure is to allow sufficient time for the priorcommand to be completed. This acknowledge signal is labeled XACK and isoutput by an inverter 1348 or 1374.

An eight-bit shift register 1342 is part of the acknowledge circuit. Theshift register is of the type 74LS164 manufactured by Texas Instruments,Inc. The shift register 1342 is incremented by the CLK signal and takesa bit of data that is input to the shift register 1342 and clocks itthrough a defined number of clock pulses. This in effect delays theoutput signal by the number of clock pulses that the bit shifted. Theinput is received from a NOR gate 1344 which has one input connected tothe BUS 1 SEL signal and the other input connected to the DACK1 signal.The B input of the shift register 1342 is connected to the output of aNOR gate 1346 which has one of the inputs thereof connected to the IOWCsignal received from the bus. The input of the inverter 1348 isconnected to the output of a NOR gate 1350, the inputs of which areconnected to the DACK0/ACK signal and an inverter 1352. The input of theinverter 1352 is connected to the output of the shift register 1342.

An inverter 1354 has the input connected to the IORC command from thebus and the output thereof connected to the input of an inverter 1356.The output of the inverter 1356 is connected to one input of a NAND gate1358. The output of the NAND gate drives one input of a flip-flop 1360and the other input of the flip-flop is connected to the output of theinverter gate 1364. The output of the flip-flop 1360 is connected to theinput of a NAND gate 1362, the other input of which is connected to theoutput of the inverter 1354. The input of the NAND gate 1358 that isconnected to the other input of the flip-flop 1360 is driven by aninverter 1364 that has its input connected to the DACK1 signal. Theoutput of the inverter 1364 is also connected to one input of a NANDgate 1366 which has the other input thereof connected to the I/O CMDsignal line. The output of the NAND gate 1366 supplies a DMA READYsignal to the DMA controller 1422. The DMA READY signal output by theNAND gate 1366 is a synchronizing signal to synchronize the I/O readcommand on the bus to the DMA READ register function because, althoughthey are supposed to be synchronous, in actuality, they areasynchronous.

A NOR gate 1368 has one input thereof connected to the RESETA signal,the other input thereof connected to the INIT signal from the bus andthe output thereof connected to the input of an inverter 1370 and oneinput of a NAND gate 1372. The other input of the NAND gate 1372 isconnected to the RESET signal from the CPU 1330. The output of theinverter 1370 supplies the RESET IN signal which is supplied to the CPU1330. The output of the NAND gate 1372 is connected to a pair ofinverters 1374 to provide buffering and also outputs the acknowledgesignal XACK signal to the bus. The NAND gate 1372 is operable to providethe acknowledge signal XACK to the bus to indicate that the RESETcommand that was generated for the CPU 1330 has been carried out.

A NAND gate 1376 has one input thereof connected to the address-enablestrobe AEN, the other input thereof connected to the ADSTB signal of theDMA controller 1422 and the output thereof connected to one input of aNOR gate 1378. A NAND gate 1380 has one input thereof connected to theALE output of the CPU 1330, the other input thereof connected to the AENsignal and the output thereof connected to the other input of the NORgate 1378. The output of the NOR gate 1378 is connected to the IC 1322.The NAND gates 1376 and 1380 and the NOR gate 1378 comprise amultiplexer for the address-enable strobe on the IC 1322.

A chip select circuit 1390 and a chip select circuit 1392 performdemultiplexing of the address on the internal bus 1322. The chip selectcircuit 1390 receives the AC, AD and AE inputs and demultiplexes this3-bit address into eight outputs. The chip select circuit 1392 receivesthe AB, AC, and AD inputs and demultiplexes this 3-bit address intoeight outputs. The chip selects 1390 and 1392 are of the type 74LS138manufactured by Texas Instruments, Incorporated. Three of the outputs ofthe chip select circuit 1390, CS16, CS18 and CS20, are input into ajumper matrix 1394. Three of the outputs from the chip select circuit1392, CS00, CS02, and CS04, are also input to the jumper matrix 1394.The matrix 1394 outputs the chip select signals for a desired ROM. Theoutputs are CSR0M0, CSROM1, and CSROM2 corresponding to three separateROMs. It should be understood that more than three ROMs may be included,which would require additional addresses. The jumper matrix 1394 outputsa PROM SEL signal and receives two bits of data, AB and AF, from theinternal bus 1332. The signal AF on the internal bus 1332 controls theenable operation of the chip select circuit 1390.

A ROM 1400 has the address inputs A0-AA connected to the internal bus1332 and the data outputs AD0-AD7 connected to the internal bus 1320. AROM 1402 has the address inputs A0-AA connected to the internal bus 1322and the data outputs AD0-AD7 connected to the internal bus 1320. A ROM1404 has the address inputs A0-AA connected to the internal bus 1332 andthe data outputs AD0-AD7 connected to the internal bus 1320. The ROM1400 is controlled by the signal CSROM0, the ROM 1402 is controlled bythe signal CSROM1, and the ROM 1404 is controlled by the signal CSROM2.The signal PROM SEL selects the EPROMS 1400-1404. The EPROMs of the type2716 provide 6K of ROM memory space. EPROMs of the type 2732A can beutilized to provide 12K of ROM memory space. Each of the ROMs 1400-1404has the RD signal connected thereto to allow the CPU 1330 to read theinformation contained therein. The information is located in each of theROMs 1400-1404 by inputting the correct address on the lines A0-AA onthe internal bus 1332.

A RAM 1406 has the address inputs A0-A9 connected to the internal bus1332 and the address/data inputs AD0-AD3 connected to the bus 1320. ARAM 1408 has the address inputs A0-A9 connected to the internal bus 1332and the address/data inputs AD4-AD7 connected to the internal bus 1320.A RAM 1410 has the address inputs A0-A9 connected to the internal bus1332 and the address/data inputs AD0-AD3 connected to the internal bus1320. A RAM 1412 has the address inputs A0-A9 connected to the internalbus 1332 and the address/data inputs AD4-AD7 connected to the internalbus 1320. The RAMs 1406 and 1408 comprise a complementary pair and theRAMs 1410 and 1412 comprise another complementary pair. The RAMS1406-1412 have the capability to receive and store data from theinternal bus 1320 and output data to the internal bus 1320. A signalCS06 is connected to the complementary pair of RAMs 1406-1408 andenables this pair to either write data on or read data from its internalbus 1320. A write enable signal WE controls this operation. Thecomplementary pair of RAMs 1410-1412 is controlled by a CS07 signal. TheCS06 and CS07 signals are operable to select either pair of RAMs. Theaddress A0-A9 and AA determines the area of memory space within the RAMs1406-1412 that the information is either stored in or retrieved from theRAMs 1406-1412 which are of the type 2114 in manufactured by MostekIncorporated.

A three-input NAND gate 1414 provides the signal CS06 and a three-inputNAND gate 1416 provides the signal CS07. The data bit AA from theinternal bus 1332 is input to one input of the NAND gate 1416 and isinverted by an inverter 1418 and then input to one input of the NANDgate 1414. The RAM select signal CSRAM from the chip select circuit 1392is passed through an inverter 1420 and input to one input of both theNAND gate 1414 and the NAND gate 1416. The remaining inputs for the NANDgates 1414 and 1416 are the READ or WRITE ENABLE signals, RE+WE. TheNAND gates 1414 and 1416 allow the circuit microboard to read or writeon the internal RAM when the CSRAM signal is present from the chipselect circuit 1392.

A DMA controller 1422 interfaces with the internal bus 1320 on addressdata lines AD0-AD7 and also interfaces with the internal bus 1332 on theaddress lines A0-A7. The DMA controller 1422 is of the type 8257manufactured by INTEL Corporation. The DMA controller 1422 is a slaveCPU that assists the CPU 1330 by performing some functions such as readand write independent of the CPU 1330. This provides for more efficientuse of CPU time. The DMA controller 1422 generates the address linesA0-A7. A latch circuit 1424 of the type 8212 manufactured by INTELinterfaces with the address data lines AD0-AD7 on the internal bus 1320and is operable to demultiplex these address data lines to the higherorder address lines AA-AF on the internal bus 1332. A strobe signal fromthe controller 1422 is connected to the strobe input of the latch 1424to latch the address over from the internal bus 1320 to the internal bus1332. The strobe signal also is connected to one input of the NAND gate1376 that performs a multiplexing function for the IC 1322.

A NAND gate 1426 has one input thereof connected to the MEMR signal fromthe DMA controller 1422 and the other input thereof connected to theaddress enable signal AEN and the output thereof connected to one inputof a NOR gate 1428. A NAND gate 1430 has one input thereof connected tothe RD signal, the other input thereof connected to the AEN signal andthe output thereof connected to the other input of the NOR gate 1428. ANAND gate 1432 has one input thereof connected to the output of aninverter 1434, the other input thereof connected to the WR signal andthe output thereof connected to one input of a NOR gate 1436. The inputof the inverter 1434 is connected to the AEN signal. A NAND gate 1438has one input thereof connected to the AEN signal, the other inputthereof connected to the MEMW output by the DMA controller 1422 and theoutput thereof connected to the other input of the NOR gate 1436. Theoutput of the NOR gate 1436 is connected to one input of a NOR gate1440, the other input of which is connected to the output of the NORgate 1428. The output of the NOR gate 1436 is also interconnected withthe WE signal. The output of the NOR gate 1440 provides the READ orWRITE ENABLE signal, RE+WE, which is input to the NAND gates 1414 and1416. The gates 1426-1440 provide a logic memory interface to allow theDMA controller 1422 and the CPU 1330 to access the same RAM spacethereby providing a multiplexing function. Whenever the controller 1422desires to do a memory read or a memory write for the RAMs 1406-1412,either a memory write MEMW or a memory read MEMR is generated and inputto the NAND gates 1426 and 1438, respectively. These gates are part ofthe multiplexer for the RAM.

Parallel to serial and serial to parallel converters 1442 and 1444interface with the internal bus 1320 on the address lines AD0-AD7 toconvert a parallel address word to a serial bit stream that is thenconnected to the Delta Modulator. The converters 1442 and 1444 areoperable to receive serial data from the Delta Modulator and convert itto parallel data for transfer along the internal bus 1320 to the RAM andfor reception of data from the internal bus 1320 and sent serially tothe Delta Modulator. The converters 1442 and 1444 comprise the Codecinterface logic 140 of FIG. 8. The input data is input to the DATA LINEof the converter 1442. The output of the converter 1442 is connected tothe input of the converter 1444 by a connecting line 1445. Theconverters 1442 and 1444 are of the type 74LS395 manufactured by TexasInstruments, Inc.

The output of the converters 1442 and 1444 to the Delta modulator isoutput by a synchronizing circuit 1446 that is a D-type flip-flop of thetype 74LS74 manufactured by Texas Instruments, Inc. which receives thedata input from the output of the converter 1444. The synchronizer 1446outputs a bit stream that is in the proper synchronization format forthe Delta Modulator which is necessary since the bit stream output bythe converter 1444 is slightly out of synchronization. D-type flip-flops1448 and 1450 are connected in a configuration to form a quasi-one-shotfunction. The modulator clock MODCK.1 from the IC 1322 is input to theclock input of the D-type flip-flop 1450 and the output of the D-typeflip-flop 1448 is a short pulse for each clock pulse that is present.The Q output of the flip-flop 1448 is input to the clock input of thesynchronizer circuit 1446 and the Q output thereof is input to one inputof a NOR gate 1452 that outputs a clock signal Clock to the input of theconverters 1442 and 1444. A counter-circuit 1454 generates a signal forthe DMA logic to read another byte or to write another byte for theconverters 1442 and 1444. The signal is labeled BUFF FULL. The circuitcounter 1454 is of the type 74161 manufactured by Texas Instruments,Inc.

A J-K flip-flop 1456 is operable to generate a terminal count signal,TC, that is an interrupt signal to indicate that the DMA register hasreached its terminal count and requires service. The input for the J-Kflip-flop 1456 is received from the terminal count output TC of thecontroller 1422 and the other input of the J-K flip-flop 1456 is fromthe TC/ACK signal for terminal count knowledge. A D-type flip-flop 1458is operable to synchronize the DACKO signal output by the DMA controller1422. An output of the D-type flip-flop 1458 is input to one input of aNAND gate 1460, the output of which is the DRQ0 or DMA request signal.The other input of the NAND gate 1460 is connected to the output of aNOR gate 1462 configured as an inverter. A NAND gate 1464 has one inputthereof connected to the DMAWR signal, the other input thereof connectedto the bold acknowledged signal, HLDA, and the output thereof connectedto the inputs of the NOR gate 1462. A NAND gate 1466 has one inputthereof connected to the DMARD signal, the output of which provides theDRQ1 input to the DMA controller 1422. The gates 1462-1464 synchronizethe bus control lines and the command lines using the DMAWR from thedemultiplexer 1306. These gates provide synchronization and alsogenerate the DMA request signals. When the controller 1422 requires theuse of the internal buses, a signal for hold request, HOLD, is generatedby the DMA controller 1422 and the CPU 1330 relinquishes control of theinternal bus to the controller 1422. The HLDA signal is generated by theCPU 1330 to indicate that the CPU 1330 has finished its cycle on the busand the controller 1422 can begin utilizing the internal buses.

A NAND gate 1468 has one input thereof connected to the inverted AENsignal, AEN, that is inverted by an inverter 1470, the other inputthereof connected to the DACK2 signal inverted by an inverter 1472 andthe output thereof connected to one input of the NOR gate 1452. A NANDgate 1474 has one input thereof connected to the inverted RD signalinverted by an inverter 1476, the other input thereof connected to theinverted DACK2 signal and the output thereof connected to the converters1442 and 1444 to provide a READ signal. The gates 1452, 1468, and 1474provide an interface between the Codec and the internal bus on thecircuit microboard.

A NAND gate 1478 has one input thereof connected to the output of theinverter 1476 to receive the inverted RD signal, the other outputthereof connected to the inverted CS10 signal inverted by an inverter1480, and the output thereof connected to the J-K flip-flop 1456 toprovide the TC/ACK signal. J-K flip-flop 1456 puts out the terminalcount TC that indicates that the terminal count has occurred and theNAND gate 1478, which outputs the TC/ACK signal, indicates that a readand chip select function has been acquired by the system andautomatically resets the interrupt so that the interrupt is processed.

A J-K flip-flop 1457 receives the output of the counter circuit 1454labeled BUFF FULL on the J-input thereof that indicates a full buffer.The K input thereof is connected to the DACK2 output of the DMAcontroller 1422 and the Q output thereof is connected to the DRQ2 inputof the DMA controller 1422. The J-K flip-flop 1457 provides the DMArequest signal to the DMA controller 1422.

Input-output (I/O) circuits provide interfaces to the internal bus 1320on the address/data lines AD0-AD7. The I/O circuit 1490 interfaces tothe internal bus 1320 and to the lines A0 and A1 of bus 1332 and to theread, write and system wide reset signal, RESET. The I/O circuit 1490 isprogrammed primarily as an output chip in the present application. Itprovides eight outputs to a group of eight LEDs 1492 on a front panel.Each of the eight LEDs in the group 1492 is internally regulated by anindividual series resistor connected between the positive voltage supplyand the anode of each of the LEDs. A group of eight buffers 1494 areutilized to drive the LEDs. Each LED is provided with one driver tointerface between one of the outputs of the I/O 1490 and the cathode ofone of the LEDs in the group 1492. The I/O 1490 also outputs the digitalcode for the DTMF tone generator 166 of FIG. 9 on the output linesmarked C0-C3 and R0-R3. The outputs marked G0-G3 control the AGC circuit160 on the analog board of FIG. 9. Also provided as outputs are theDECODE/ENCODE, the LOOP BACK and the SUPV OUT which is the supervise outthat is transmitted to the analog board at a proper level for the VCA toconnect to the phone line. The I/O 1490 also outputs a modulator resetsignal MOD RESET that resets the Delta Modulator to a known state.

An I/O circuit 1496 is identical to the I/O 1490 except that it isprogrammed for input only. The I/O 1496 is interfaced to the internalbus 1320 on the lines AD0-AD7 and interfaced to the internal bus 1332 onthe lines A0 and A1 and the I/O 1496 also receives the inputs RD, WR,and RESET, for read, write and system reset, respectively. Three inputsto the I/O 1496 labeled SW0, SW1, and SW2 are connected to a group ofswitches 1498 that switch each of these lines independently to ground.Five of the inputs on the I/O 1496 are attached to the addresses AA0-AA4that are output from the circuit 1300 to allow the I/O 1496 to read theaddress of the particular circuit microboard when it's inserted into thebus. The SUPV IN is the supervised in signal that comes from the VCA andgets buffered by the analog board of FIG. 25 to provide an indicationthat there is a connection to the telephone line. The input labeled RINGis a ring signal which comes from the VCA 16 and gets buffered to theanalog board and it provides an indication that the telephone line has aringing signal on it and needs servicing. The signals TL0-TL3 andTH0-TH3 are received to indicate the low and high tones. The signalsL0-L4 are received from the analog board to indicate the level of theincoming signal.

A timing interrupt circuit 1500 is interfaced to the internal bus 1320on lines AD0-AD7 and also interfaced to the internal bus 1332 on linesA0 and A1. The IC 1500 also receives the RD and WR signals. A D-typeflip-flop 1502 receives the CLK signal and divides it down to a rate atwhich the IC 1500 can count and perform a timing interrupt function. Theoutput is buffered by an inverter 1504 to output a TIMER signal.

Referring now to FIGS. 27a and 27b, there is illustrated a flow chartfor an alternate embodiment of the VMS system for sending and receivingmessages and setting up the various primitives, as will be describedhereinbelow. The flow chart is initiated with a START block 1510 andthen proceeds along two branches to either a function block 1512 labeledVMS CALLS USER or a function block 1514 labeled USER CALLS VMS. Thefunction block 1514 is utilized whenever a user desires access to theVMS system to either send or receive a message. The function block 1512is utilized whenever VMS calls the user. As will be describedhereinbelow, there are certain circumstances in which VMS takes theinitiative of calling a user to deliver the message without the userhaving to retrieve the deposited message.

Play-a-Port

After the connection between VMS and the user has been achieved, theprogram flows to a decision block 1516 to decide whether a PLAY-A-PORTfeature has been activated. The PLAY-A-PORT feature is a systemparameter that is controlled by the system operator to deposit generalmessages for transmission to each user in the user's data base whenevera telephone connection is made. For example, it may be necessary toservice the system and a prerecorded message is output to each user uponaccess to the system, such as "Hello, this is VMS. We are sorry but thesystem will be down on (date) for service". This feature is also usefulfor announcing daily messages to the users regarding such items as stockquotes, recently implemented and future VMS features and anything elsethat would constitute a daily or periodic announcement. If thePLAY-A-PORT feature is activated, the program flows along the "Y" pathto a function block 1518 and the prerecorded message is played for theuser's benefit. If the feature is not activated, the program follows the"N" path to bypass the function block 1518.

Password

The next step in the flow chart is to proceed to a function block 1520wherein the user I.D. is processed. When VMS calls the user, the userI.D. is processed by the procedure depicted in the flow chartillustrated in FIG. 16 and when the user calls VMS, the user I.D. isprocessed by the procedure depicted in the flow chart in FIG. 12. Afterthe user I.D. is processed, the program flows to a decision block 1522to inquire whether the password primitive has been activated. As will bedescribed hereinbelow, primitives are features of a system that a useris afforded to either expand or restrict his particular voice mailboxClass of Service (C.O.S.). The user purchases a general C.O.S. thatcontains the various primitives that are available to the user. However,there are many different C.O.S.'s available, each with its own set ofprimitives.

A password is similar to a user I.D. in that it affords the user accessto the system. However, the password is only known to the user and to noone else. The user's I.D. number is normally given to him by a systemadministrator who, along with several other people, have access to theuser's I.D. The password, on the contrary, is entered only by the userand only the user has knowledge of the password. If the passwordprimitive has been activated in a function block described hereinbelow,the program flows along the "Y" path to a function block 1524 whereinthe password is entered. After the password is entered, the programflows to a function block 1526 and the password is compared to thepreviously entered and stored password (described hereinbelow). Althoughnot shown, an invalid password will cause the program to return to theinput of the function block 1524 whereas a valid password advances theprogram to a decision block 1528. If the password primitive has not beenactivated, the program flows along the "N" path of the decision block1522 to the input of the decision block 1528.

Auto Inquiry

The decision block 1528 decides whether the AUTO INQUIRY function isactivated. AUTO INQUIRY is a primitive of the user's C.O.S. and enablesthe user to automatically bypass the requirement for inputting a SpecialFunction Code (SFC) to receive messages. If AUTO INQUIRY is turned on,the flow chart proceeds along the "Y" path to a function block 1530labeled RECEIVE A MESSAGE which will be described hereinbelow withreference to FIGS. 29a and 29b. If AUTO INQUIRY is not on, the programflows along the "N" path to a decision block 1532 to decide if the userhas dialed any digit except "0". If the user has dialed "0", the programflows along the "N" path to a decision block 1534. The decision block1534 decides whether the user has dialed the digits "011". If the digits"011" have been dialed, the program proceeds along the "Y" path to theinput of the function block 1530 to enable the user to receive messages.If the user has dialed digits other than "011", the program returnsalong the "N" path thereof. The decision blocks 1532 and 1534 are theprimary logic steps that the AUTO INQUIRY feature in decision block 1528eliminates and, as such, the need to dial "011" to receive messages thatare deposited is eliminated by AUTO INQUIRY. When AUTO INQUIRY isactivated, after the user I.D. has been processed and a possiblepassword entered, VMS automatically checks to see if there have been anymessages deposited for the user, as will be described hereinbelow withreference to FIGS. 29a and 29b.

Referring back to the decision block 1522, if the user dials a digitother than "0", the program flows along the "Y" path to a function block1536 labeled SEND A MESSAGE. The SEND A MESSAGE function block 1536 isoperable to allow the user to record a message for deposit in anotheruser's mailbox or for delivery to a non-user, as will be describedhereinbelow with reference to FIG. 28. After a message has beendeposited, the program returns to the input of the decision block 1528.

Name Play

After the user has opted to either send a message or to receive amessage already deposited in his message address, the program proceedsto a decision block 1538 to decide whether the user desires to activatethe NAME PLAY feature. This feature allows the user to listen to thename of the message originator in the message originator's own voice.The message originator's name is prerecorded by the originator-userhimself for retrieval with each message that the originator deposits ina recipient's message address. When a message is retrieved from a user'smessage address, the message begins with the name of the originator andthen proceeds to the remaining text of the original message. Forexample, a user retrieving a message would hear "Hi, this is John Doe"followed by the full text of the message. This feature allows the userto determine if he wants to hear the remaining portion of the message orto save that message and go on to another message. In addition, thisfeature allows the user to skip through a plurality of messages that maybe in his message address and only listen to those messages by aparticular originator. An important aspect of this feature is that theoriginator's name is voiced by the originator himself. This providesboth a more humanized greeting than the voice of VMS itself and an auralrecognition of the originator. This aural recognition permits a user toterminate the message merely by the sound of the originator's voicebefore the entire name is heard. It should be understood that once theoriginator-user deposits his name in the user's data base, this featureis available to all recipients of messages from the originator-user thathave the NAME PLAY feature available in their C.O.S.

If the NAME PLAY feature is activated, the program flows along the "Y"path to a decision block 1540. The decision block 1540 inquires as towhether a NAME PLAY C.O.S. is activated. If the C.O.S. is activated, theprogram flows along the "Y" path to a decision block 1542 to decidewhether the NAME PLAY feature is enabled or not. If the NAME PLAYfeature is enabled, the program flows along the "Y" path to a functionblock 1544 that turns off the NAME PLAY feature and then returns to themain program. If the NAME PLAY feature is not enabled, the program flowsalong the "N" path to a function block 1548 that turns on the NAME PLAYfeature and then returns to the main program. If the NAME PLAY C.O.S.has not been activated, the decision block 1540 returns to the mainprogram thus preventing a particular user that has not purchased thisC.O.S. from accessing this feature. As described hereinabove, aparticular C.O.S. must be activated from the central office and not by aparticular user.

Name Record

If the user having the NAME PLAY feature in his C.O.S. does not requestthe feature, the program proceeds to a decision block 1550. The decisionblock 1550 decides whether the user has requested a feature termed NAMERECORD. NAME RECORD is the step whereby a user's name is deposited inthe VMS memory banks for transmittal with each of the user's depositedmessages. If the user requests the NAME RECORD feature, the programflows along the "Y" path to a decision block 1552 that decides whetherthe NAME PLAY C.O.S. is activated. If this C.O.S. is not activated, theprogram flows along the "N" path and returns to the main program and ifthis C.O.S. is activated, the program flows along the "Y" path to afunction block 1554 wherein VMS prompts the user to record his name. Theprogram then flows to a function block 1556 where the user dials a "1"and then to a function block 1558 where the user speaks his name. Itshould be understood that the user can introduce any message he desiresat this point within reasonable limits depending upon his particularrequirements, that is, it does not necessarily have to be the user'sname. After the user has deposited his name and/or message, the programflows to a function block 1560 where the user dials a "5" to advance theprogram to a function block 1562 where the VMS stores the spoken nameand/or address in the user's data base. The program then returns to themain program at the "N" path of the decision block 1550.

At certain times, a particular user may not desire to listen to thespoken name of each of the message originators that has depositedmessages in the user's mailbox. This is the purpose of the toggleoperation of the function blocks 1544 and 1548, namely, the user canturn off this function if he so desires. It should be understood thatwhen the NAME PLAY feature is enabled, a user must listen to at leastone name before he can terminate this feature. However, normally thesystem is initiated in the disabled mode such that a user must activelyenable the feature to have it present.

Group Codes

If the NAME RECORD feature is not selected, the program flows from thedecision block 1550 along the "N" path to a decision block 1564. Thedecision block 1564 decides whether a user has dialed the command forGROUP CODES. If the user has requested GROUP CODES, the program flowsalong the "Y" path to a function block 1566 to a USER CHANGEABLE GROUPCODE feature that is described hereinbelow with reference to FIG. 31.The program then returns to the main program.

Enter New I.D.

If the user has not dialed the command for GROUP CODES, the programflows along the "N" path to a decision block 1568. The decision block1568 decides whether the user has dialed the SFC "056". If the user hasdialed this SFC, the program flows along the "Y" path and returns to theinput of the function block 1520 to reprocess the user I.D. The purposeof the decision block 1568 is to allow a user the option to enter a newI.D. without having to exit the program, terminate the telephoneconnection and reaccess the VMS. The primary purpose for this feature isfor users who have a number of different addresses to access a differentaddress without having to disconnect and reconnect to VMS. One reasonfor a user having a number of different addresses is to possessaddresses that are not listed in the general directory, therebyaffording the user the luxury of a "private" line. This is similar tohaving an unlisted phone number for a separate phone in an office.

If the user does not desire to enter a new user I.D., the program thenflows along the "N" path to a decision block 1570. The decision block1570 decides whether the user has dialed the SFC "057". If the user hasdialed this SFC, the program flows along the "Y" path to a functionblock 1572 that is a subroutine for retrieving the address list that wasentered by the user while he was sending his previous message. Thisaddress is used in sending the next message. This allows a user to sendanother message to the previous addressee or even a group of addresseeswithout having to reenter an address. After the address list has beenretrieved, the program proceeds to a function block 1574 which routesthe program into the SEND A MESSAGE program of FIG. 28, as will bedescribed hereinbelow.

If the user has not dialed the SFC for the address retrieval feature,the program flows along the "N" path to a decision block 1576. Thedecision block 1576 decides whether the user has dialed the SFC "054".This SFC is for inputting a new password for later processing in thedecision block 1522 and the function blocks 1524 and 1526. If a newpassword is desired, the program proceeds along the "Y" path to afunction block 1578 wherein VMS requests a new password from the userand then proceeds to a function block 1580 where the user inputs the newpassword which is stored in VMS. The program then returns to the mainprogram at the "N" path of the decision block 1576 which would befollowed if the SFC for the new password were not dialed. The program ofFIG. 27 then proceeds to a return block 1582 to return to the mainprogram for the system.

Priority Hold

The PRIORITY HOLD feature allows a user to place VMS in a mode wherein apriority message can be automatically relayed to the telephone of theuser. For example, if VMS were instructed to give priority to messagesfrom user "X", VMS would automatically dial the user's telephone ratherthan deposit the message in user's address, thereby forcing delivery ofthe message. In this manner, the user has immediate access to messagesfrom desired users. There are four criteria that a user can utilize toinstruct VMS to force deliver the messages to the user. The criteria areas follows:

(a) Any priority or non-priority voice messages in user's messageaddress.

(b) Any priority voice messages in user's message address.

(c) Any priority or non-priority voice messages from a particularaddressee in user's message address.

(d) Any priority voice message from a particular addressee in user'smessage address.

The priority nature of a message is determined by an SFC input by theoriginating user of the message. If this SFC is input to VMS when themessage is recorded, the nature of the message is then priority and willbe transferred according to the above criteria. For example, in acorporate environment, there are many situations which require immediateattention from a supervisor. By placing a priority nature on a voicemessage, a user can insure that the voice message is handled in anexpedient way. However, it should be understood that it is necessary forthe selected recipient to input the proper SFC to select immediatereceipt of a priority voice message.

Time--I.D. Validity

The TIME--I.D. VALIDITY feature provides a user the versatility todetermine a "window" within which a selected recipient can receive amessage. An SFC is input to access this feature, and then an analogprompt from VMS asks for the time and date after which VMS shouldattempt to deliver the message to the selected recipient's address foraccess thereof. If the user desires to send the message only after acertain date, he inputs a time and day. However, if the user does notdesire to restrict the time and day at which VMS first attempts todeliver the message, he inputs another SFC to bypass this portion of thefeature. VMS then prompts the user to enter a time and day wherein themessages will be deleted. This in effect prevents "stale" messages frombeing delivered to a recipient who may, for some reason, be unavailable.

Shared System

SHARED SYSTEM is a feature that allows a plurality of companies of usersto share a common VMS. This situation occurs, for example, where acompany does not have a requirement for storing a great deal ofmessages. As the storage capability of a VMS is finite, only a certainnumber of messages can be stored at any given time. By sharing thememory space, a large number of users can utilize the same memory spaceand even the same user I.D.'s. The various ports that are available on aVMS system must be divided among the companies. This is the onlyrestriction that the companies have. In addition, the differentcompanies can access users between the companies. This requires only anintercompany transfer code followed by the message address of the userin the adjacent company.

Referring now to FIG. 28, there is illustrated the flow chart for theSEND A MESSAGE function of function block 1536 of FIG. 27. The programflows from the function block 1536 to a function block 1584, wherein thedigits of an addressee are entered by the user. After the digits areentered, the program flows to a decision block 1586 to decide whetherthe digits are for a user or for a non-user. A user would have digitsthat are stored and would have a mailbox that a message could bedeposited in. A non-user, unlike the user, must have the messagedelivered directly to him rather than deposited in a message address. Ifthe message addressee is a user, the program proceeds along the "N" pathto a function block 1588 to process the user addressee.

The function block 1588 is similar to the subroutine depicted in FIG.13. If the message addressee is a non-user, the program proceeds alongthe "Y" path to a function block 1590 where the digits for the non-useraddressee's telephone station are stored in the VMS system.

Restricted Dialing Pattern

After the addresses for the user or non-user are processed, the programflows from the function block 1588 or 1590 to the input of a functionblock 1592 where the VMS system accesses the allowable dialing tableC.O.S. list. This allowable dialing list provides the VMS system withthe capability of restricting the access that a user has to thetelephone systems. For example, some users may have the ability tocommand VMS to dial long-distance phone numbers to reach a particularmessage addressee. However, long-distance calls require additionalexpense, and, as such, must be accounted for in the C.O.S. that a useris entitled to. This restriction can apply to the user's access oflong-distance users, local users, local non-users, networking (describedhereinbelow), and many other features.

Once the allowable dialing table has been retrieved, the programproceeds to a function block 1594 wherein the first pattern is selected.After selection, the program proceeds to a decision block 1596 to decideif the pattern is allowed. If allowed, the program flows along the "Y"path to a decision block 1598 and if disallowed, it flows along the "N"path to a decision block 1600. The decision block 1598 decides whetherthe digit string itself is allowable and if so, the program proceeds toa decision block 1602 and if disallowed, the program proceeds along the"N" path to the input of the decision block 1600.

Personal Group Codes

In the situation where the pattern is disallowed the program proceeds tothe input of the decision block 1600 where a decision is made as towhether the pattern is the last pattern in the dailing table. If thereare additional patterns to compare the addressee's address with, theprogram proceeds along the "N" path to a function block 1604 to selectthe next pattern and then returns to the input of the decision block1596. Once the last pattern has been processed, the program flows to adecision block 1606 along the "Y" path to decide if the pattern fitswithin the PERSONAL GROUP CODE pattern. PERSONAL GROUP CODE is a featurethat consists of a group of addresses associated with a particular userand has a pattern that is delineated by the particular user. Thispattern is normally input by the system operator as a "customized"feature that essentially associates a pattern of digits with the user'sI.D. such that a user can access stored information with these digits.PERSONAL GROUP CODES would be oriented toward things such as lists ofmembers on a bowling team or the tennis team or some committee that theuser is on himself. This is generally a short list or group of peoplethat would be of interest only to a particular user. As will bedescribed hereinbelow, this group code can be altered by the user addingor deleting names therefrom.

Universal Group Code

If the pattern fits the personal group code pattern, the program flowsalong the "Y" path to a function block 1608 to access the address list.If the pattern does not fit, the program proceeds along the "N" path toa decision block 1610 that decides whether the pattern fits a UNIVERSALGROUP CODE pattern. The UNIVERSAL GROUP CODE pattern is similar to thePERSONAL GROUP CODE except that it is a permanent group code that isnormally set up by a company that owns the VMS system. This type ofgroup code would contain groups like all department managers, allsupervisors or all officers and these groups are accessible by all usersassociated with the user's data base. The PERSONAL GROUP CODE, on theother hand, is only accessible by the user within the restrictions ofthe group code pattern set up by that user. If the pattern does fit theUNIVERSAL GROUP CODE pattern, the program proceeds along the "Y" path toa function block 1612 that accesses the address list. Once the addresslist is accessed in either function block 1608 or 1612, the programproceeds to a function block 1614 where the user digit string isreplaced with the address list. The program then returns to the mainprogram.

Referring back to the decision block 1598, if the digit string wereallowable, the program would proceed along the "Y" path to the input ofthe decision block 1602. The decision block 1602 determines whether theuser had dialed an SFC "0" that determines whether the user wishes torecord a message or not. If the user wishes to record a message, theprogram flows along the "Y" path to a function block 1616 which issimilar to the subroutine of FIG. 14 to record a message. If the userdoes not wish to record a message, the program returns to the input ofthe function block 1584 to dial the digits of a new addressee.

Future Delivery

After a message has been recorded in function block 1616, the programproceeds to a decision block 1620 to decide if the user has dialed theSFC for FUTURE DELIVERY. The FUTURE DELIVERY feature allows the user tospecify a time and date in the future when the message should bedelivered. This even allows a user to ring his own telephone at apredetermined time. Within reasonable constraints, this time can be onthe order of days, weeks or months. If the FUTURE DELIVERY SFC has beenentered, the program flows along the "Y" path to a function block 1622wherein the time and date for delivery are entered and if the feature isnot selected, the program flows to the input of a RETURN block 1624. Theprogram also flows to the RETURN block 1624 from both the decision block1610 and the function block 1614 along the "N" path thereof.

Referring now to FIG. 29, there is illustrated a flow chart for theRECEIVE A MESSAGE subroutine of function block 1530 of FIG. 27. Afterthe RECEIVE A MESSAGE subroutine has been entered, the program flows toa decision block 1626 to decide if there are any messages present thatare addressed to the user. If there are no messages present, the programflows to a function block 1628 wherein VMS plays the CVM "No Message"and then proceeds to a function block 1630. The function block 1630transfers the program to the SEND A MESSAGE subroutine 1536 of FIG. 28so that the user has the option to send a message if there are no voicemessages delivered to his address. It should be understood that this isalso a function of the AUTO INQUIRY feature of decision block 1528 ofFIG. 27 in that if AUTO INQUIRY is on, the program proceeds into theRECEIVE A MESSAGE subroutine and then proceeds out of the RECEIVE AMESSAGE subroutine to the SEND A MESSAGE subroutine.

Old and New Message Que

If there are messages, the program proceeds along the "Y" path out ofthe decision block 1626 to a decision block 1632 to decide if the userhas dialed the SFC "2". This SFC decides whether to select a new messagefrom a NEW MESSAGE QUE. If the user desires a new message, the programproceeds along the "Y" path to a function block 1634 that selects thefirst or the most recent new message for play. The NEW MESSAGE QUE isactually an accumulation of new messages deposited by other originatorsin addition to non-delivered messages that have a non-deliverynotification attached (NDN). After the message is played and the usersaves the message, the message is then inserted into an OLD MESSAGE QUEand the program proceeds to the input of a decision block 1636.

If the user does not desire to listen to new messages, the programproceeds to a decision block 1638 to decide if the user has dialed theSFC "8". This SFC determines if the user wishes to select an old messagefrom the OLD MESSAGE QUE for replay. If the user does not desire tolisten to an old message, the program proceeds along the "N" path to theinput of the decision block 1632 to again allow the user the option ofselecting a new message. If the user desires to select an old message,the program proceeds along the "Y" path to a function block 1640. Thefunction block 1640 selects the first old message from the OLD MESSAGEQUE for replay and then deletes the message. However, a user can savethe old message, but this message then becomes the last message in thelist. The NEW MESSAGE QUE and the OLD MESSAGE QUE allow the user todistinguish between two types of messages, new messages and oldmessages. In addition, the NDN messages are also stored in the NEWMESSAGE QUE. This allows the user to listen to only new messages if hedesires without having to stumble through the old messages that havebeen stored for later replay.

After listening to any messages present, the program proceeds to adecision block 1636 that determines whether the NAME PLAY C.O.S. isenabled. If the NAME PLAY C.O.S. is enabled, the program proceeds alongthe "Y" path to a function block 1642 wherein the user's data base isaccessed to retrieve the name of the originator that is associated withthe particular message deposited in the user's maibox. Once the name hasbeen accessed, the program proceeds to a function block 1644 where theoriginator's name is played. The program then proceeds to a functionblock 1646 and the time/date feature is implemented whereby VMS outputsthe time and date of the message. If the NAME PLAY C.O.S. is notenabled, the program proceeds along the "N" path of the decision block1636 to the input of the time/date function block 1646 to bypass theNAME PLAY feature.

Variable Time Scan

After the originator's name and the time/date have been output by VMS,the voice message is played as indicated by a function block 1648 thatis a subroutine similar to that depicted in 1616. Once the voice messagehas been output, the program then proceeds to a decision block 1650. Thedecision block 1650 determines whether the user has dialed an SFC 77that determines whether the AUTOMATIC VARIABLE TIME SCAN feature is tobe utilized. If this feature is desired, the program flows along the "Y"path to a function block 1652 that implements the feature and allows theuser to specify a predetermined portion of the message in time units tobe played for each message. In this manner, a user can increment througheach of the messages in his address without having to listen to thewhole message. The operation of this feature will be describedhereinbelow with reference to FIG. 31.

If AUTOMATIC VARIABLE TIME SCAN is not selected, the program flows alongthe "N" path to the input of a decision block 1654. Also, the output ofthe function block 1652 flows to the input of the decision block 1654.The decision block 1654 decides whether the user has dialed an SFC "7"which allows the user to save a message in the OLD MESSAGE QUE. If auser decides to save the message, the program flows along the "Y" pathto a function block 1656 and the message is saved and then the programreturns to the input of a decision block 1658.

Variable Volume

If the user does not desire to save the message, then the program flowsalong the "N" path of the decision block 1654 to the input of a decisionblock 1658 to decide whether the user has dialed an SFC "9" for varyingthe volume. If the user desires to increase the volume, the programflows along the "Y" path to a function block 1660, and the volume isincreased by an incremental amount, and then the program proceeds to adecision block 1662. If the user does not desire to increase the volume,the program flows along the "N" path to the decision block 1662. Thevolume increase is realized by generating a command that is input toboth the circuit micro and the circuit analog boards of FIG. 25 and 26to increase the level of the output signal.

Variable Speed

The decision block 1662 decides if the user has dialed an SFC "0". Ifthe user has dialed the SFC, the program proceeds along the "Y" path toa function block 1664. The function block 1664 commands the VMS systemto remove "QUIET TIME" from the audio message. This function provides aquasi-variable speed function whereby events such as pauses orhesitations in the voice message are not transmitted. The operation ofthis feature is described in more detail hereinbelow with reference toFIG. 33. After the QUIET TIME has been removed, the program proceeds tothe input of a decision block 1666. If the user does not desire toremove QUIET TIME, the program flows along the "N" path from thedecision block 1662 to the decision block 1666. The decision block 1666decides whether the playback has finished and, if so, the programproceeds along the "Y" path, whereas if the playback has not finished,the program proceeds along the "N" path back to the input of thedecision block 1666. The "N" path provides a looping function that,because of the finite clock period of the system's central processingunit, a time delay occurs for each loop thereof.

Once the playback has finished, the program proceeds to the decisionblock 1668. The decision block 1668 decides whether the user has dialedan SFC "021". If the user has dialed this SFC, the program proceedsalong the "Y" path to a function block 1670 to implement a REDIRECTfeature which is described hereinbelow with reference to FIG. 30. Afterthe REDIRECT feature has been implemented, the program proceeds to areturn block 1672.

Group Reply

If the REDIRECT feature is not desired, the program flows from thedecision block 1668 along the "N" path to a decision block 1674. Thedecision block 1674 decides whether the user has dialed an SFC "023". Ifthe user has dialed this SFC, the program proceeds along the "Y" path toa function block 1676 wherein VMS prompts the user to dial 1 toacknowledge and then dial "5" to reply to the message. The program thenproceeds to a function block 1678 where the user sends a reply to allusers that received the original message. The function blocks 1676 and1678 provide the feature termed GROUP REPLY. The GROUP REPLY feature isa feature that is activated after the message is received and normallyused in a committee situation. For example, after a message has beenreplied to, the GROUP REPLY command would send the reply to every personthat had received the original message. Of course, the original groupthat received the message is determined by the originator. This featureis available to everybody that received the original message such thateach recipient can send and receive replies. It should be understoodthat these replies only go to the members of the group and notnecessarily to the originator of the message unless he also is a memberof the group. To send the messages selectively to the other members ofthe group or to other users in general, the REDIRECT feature in functionblock 1670, as will be described hereinbelow, is utilized. If the userdoes not desire to reply, the program flows from the decision block 1674to the return block 1672. This is also the terminating point for theprogram after a reply has been sent to the group.

Redirect

Referring now to FIG. 30, there is illustrated a flow chart for theREDIRECT feature illustrated by the function block 1670 FIG. 29. Afterthe program has entered into the subroutine for REDIRECT, the programflows to a function block 1680 that prompts the user to enter the digitsfor the addressee. The program then proceeds to a function block 1682 toprocess the addressee, which is similar to the subroutine depicted inFIG. 13. After the addressee has been processed, the program flows to adecision block 1684 to determine if the user has dialed the SFC "0". If"0" has been dialed, the program flows along the "Y" path to record themessage and if the user has not dialed "0", the program proceeds alongthe "N" path to return to the input of the function block 1680. Afterthe addressee has been processed and the user has dialed the SFC torecord the message, the program proceeds to a function block 1686wherein VMS prompts the user to dial an SFC "1" to record a message. Theprogram proceeds then to a function block 1688 to record the message inthe manner similar to that depicted by the subroutine flow chart in FIG.14. To exit the record mode, the user dials the SFC "5". This isdepicted by a decision block 1690 that proceeds along an "N" path to theinput of the RECORD MESSAGE function block 1688 until the SFC "5" isdialed wherein the program proceeds along the "Y" path to a decisionblock 1692.

The decision block 1692 decides whether a REDIRECT attachment ispresent. The REDIRECT attachment is a previously-recorded message thatis attached to the original message by another user. For example, whenuser A wants user B to hear a message that was delivered to user A fromuser C, user A would add a short introductory message to the messagesuch as, "Hi user B, this is user A and I would like you to hear thismessage I received from user C." If the REDIRECT attachment is present,the program proceeds along the "Y" path to a decision block 1694 todecide whether the messages that are attached to the original messageshould be erased. This is a procedure whereby VMS would prompt a user todecide whether he wishes to leave the previously-attached messageintact. If the user desires so, then the program proceeds along the "N"path but, if the user desires to erase the attachment, then an SFC isentered and the program proceeds along the "Y" path to a function block1696 where the attachments are erased. After the attachments are eithererased or left intact, the program proceeds back to the main program,and input to a function block 1698.

If the REDIRECT attachment was not present in the first place, theprogram would proceed from the decision block 1692 along the "N" path tothe function block 1698 wherein the recorded message is attached to thefront of the original message. After the message has been attached, theprogram proceeds to a function block 1700 wherein the VMS routes theoriginal message with the attached messages to the particular addressee.The program then proceeds to a return block 1702 to return to the mainprogram of FIG. 29.

If a user desires to retain the previously-attached messages when heredirects the original message to another user with a new attachedmessage, the REDIRECT function allows him to do so. For example, user Asends a message to user B who redirects the original message to user Cwith an attached message. At this point, user C has two options; firsthe can redirect the original message with only his attached message to afourth user, user D, or, second, user C can redirect the originalmessage to user D with both user B's attached message and his ownattached message. This allows a series of users/recipients tosequentially redirect an original message and yet retain all of theattached messages in the string of redirecting users. Although afunction block 1698 indicates that each of the attached messages precedethe original message, it should be understood that the previous messagescan be attached to the back of the original messages and only thepresently-recorded attached message is attached to the front of theoriginal message. In addition, the original message can be redirected tothe originator.

User Changeable Group Codes

Referring now to FIG. 31, there is illustrated a flow chart for the USERCHANGEABLE GROUP CODES of function block 1566 of FIG. 27. After the userhas selected the SFC for changing a group code, the program proceeds toa function block wherein the VMS prompts the user to select which groupcode he desires to add, change or delete. The program then proceeds to afunction block 1706 where the user dials the digits to specify the listto retrieve. After the digits have been dialed, the program proceeds toa function block 1708 where VMS retrieves the list from the user's database. It should be understood that the user must have the proper C.O.S.that makes this feature available to him in order to access a particularlist. The type of lists that would be stored in the user's data basewould be such things as personal committees that the user is on, listsof the tennis team or the soccer team and even social club lists.

After the particular list is retrieved from the user's data base, theprogram then proceeds to a function block 1710 wherein the VMS promptsthe user to select the ADD or CHANGE function. The program then proceedsto a decision block 1712 to decide if the user has entered the SFC toselect the CHANGE function. If the CHANGE function has been chosen, theprogram proceeds along the "Y" path to a function block 1714. If theuser has not chosen the CHANGE function, that is, the user has dialeddigits different from the SFC, the program flows along the "N" path to afunction block 1716. If the user desires to change the list, the "Y"path is followed and the function block 1714 is where the VMSsequentially plays the name of each address in the group code list. Forexample, if the list were the members of a tennis team, then each nameon the tennis team would be sequentially played and voiced by the VMSsystem. After each of the names has been played, the program proceeds toa decision block 1717 that inquires whether the user wishes to deletethe name. If the user wishes to delete the name, the program proceedsalong the "Y" path to a delete function block 1718 and if the userwishes to retain the name, the program proceeds along the "N" path to adecision block 1720. To delete a name, the user has available to him anSFC as supplied to him by VMS as a prompt, or it is supplied to the userin the operating manual. The decision block 1720 decides whether thelast name in the group code list has been played and, if so, the programproceeds along the "Y" path to a return block 1722. If there are namesremaining in the group code list, the program proceeds along the "N"path to return to the input of the function block 1714 to increment thelist and play the next sequential name.

When a user desires to add a name to the group code list, the programproceeds from the decision block 1712 along the "N" path to the functionblock 1716 wherein the user dials the address to be added to the list.After the user has added the address, an important aspect of the presentinvention is that VMS plays back the name of the addressee to the user,as indicated by a function block 1724. This provides feedback so thatthe user is certain that he has dialed the correct address. The programthen proceeds to a function block 1728 wherein the user dials a "*" toaccept the address. After the address is accepted and stored by VMS, theprogram proceeds to a decision block 1730 to decide if the user desiresto exit this portion of the program. If the user does not wish to exit,the program automatically proceeds along the "N" path back to the inputof the function block 1716. If the user wishes to exit the routecomprised of the function blocks 1716, 1724 and 1728, the user dials a"#" and the program proceeds along the "Y" path to the return block1722.

When a user desires to add an addressee to the group code list, the userenters the address of the addressee and VMS plays back the name of theaddressee rather than the digits dialed. For example, if a user desiresto access a list of all salesmen in one portion of the United States, hewould retrieve this list and then enter the ADD portion of thesubroutine. When the VMS prompts for an address, the user enters theaddress. VMS then responds with "The address you have dialed is for JohnDoe." This alleviates the requirement for the user to search through adirectory or such to double check the address of a particular addresseesince the USER CHANGEABLE GROUP CODE verbal feedback of the name of theaddressee.

Variable Time Scan

Referring now to FIG. 32, there is illustrated a flow chart for theAUTOMATIC VARIABLE TIMESCAN feature of function block 1652 in FIG. 29.After the user has dialed "77", the program enters the subroutine forAUTOMATIC VARIABLE TIMESCAN. This SFC is normally dialed during thedelivery of a message. The SFC is dialed after a user-determined amountof time has elapsed and the program proceeds to a function block 1732wherein the length of time that the message has played is stored in thesystem memory in a position termed "X". Once this time is stored, theprogram proceeds to a function block 1734 wherein the message is savedin total. This is a similar procedure to the user dialing the SFC "7" tosave a message. After the total message is stored, the program proceedsto a function block 1736 and the next message in the user queue isretrieved. After the message has been retrieved, the system plays theoriginator's name and the time/date stamp if the proper C.O.S. has beenenabled, as shown in function block 1644 and 1646 of FIG. 29. After thepreliminary attachments are played, the message itself is played out,but only for "X" amount of time as indicated by a function block 1728.After the message has played for "X" amount of time, the programproceeds to a decision block 1740 to decide whether the user wishes toproceed to the next message or to hear the remaining portion of thepresent message. If the user takes no positive action, the programproceeds along the "N" path to the input of the function block 1734 tosave this message and retrieve the next message for playback for "X"amount of time. However, if the user decides that this message is ofparticular importance and wishes to receive the full text of themessage, the user dials an SFC "2" and proceeds along the "Y" path to afunction block 1742 that continues normal playback. After this messagehas been played, the program proceeds to a return block 1744 to returnto the original program of FIG. 29 at the input of the decision block1654.

The AUTOMATIC VARIABLE TIMESCAN feature affords the user a method bywhich he can determine the specific length of time that each message isto be played. For example, if the user has an inordinate number ofmessages in his message address, he can activate the feature afterlistening to a certain portion of the first message and he can save thisamount of time. With no further action, the user can just listen toportions of each message in his message address until he hears one thathe deems particularly important. This is a scanning function with auser-determined time factor that utilizes not only the time factor, butalso the voice of the originating user. For example, if the user issearching for a message from a friend or business associate whose voiceis familiar to him, it is only necessary to listen to a very shortportion of the message in order to make an association.

Quiet Time Compression

Referring now to FIG. 33, there is shown a flow chart for QUIET TIMECOMPRESSION 1746. QUIET TIME COMPRESSION is the ability of the VMS toremove periods of time from a recorded message during which there arepauses, low-level mumbling or generally inaudible sounds. The portion ofthe circuitry utilized for QUIET TIME COMPRESSION is found primarily inFIGS. 25a-25c. It is also somewhat software oriented in that theprogrammable gain amplifier 1044 controls a software timer in responseto the level of the sound received. The outputs L0-L4 indicate fivedifferent levels that the software utilizes to detect level. By varyingthe gain of the programmable gain amplifier 1044 and sensing the levelof the signal, VMS can compare the audio signal to an internal thresholdand increment a timer whenever the audible signals fall below thethreshold to store this time. It should be understood that the softwaretimer for QUIET TIME COMPRESSION is referenced to the elapsed time suchthat the full message can be reconstituted. For example, if a messageoriginator pauses after he has delivered approximately 10 seconds of hismessage, the duration of this pause must be added back to the message atthe proper place in the message when it is reconstituted.

During recording of a message, as indicated by the "Y" path on adecision block 1748, the program proceeds to a decision block 1750 todecide whether the voice level is above the internal software threshold.If the voice level is above the threshold, the program proceeds alongthe "Y" path and the digital data corresponding to the voice message isstored as indicated by a function block 1752. The program then proceedsto a decision block 1754 to decide if the record mode is still on and,if so, proceeds along the "Y" path back to the decision block 1750. Itshould be understood that the QUIET TIME COMPRESSION 1746 is part of theRECORD MESSAGE block 1616 of FIG. 28 which is referenced to FIG. 14.

If the voice level falls below the threshold, the program proceeds alongthe "N" path of the decision block 1750 to a function block 1756 whichstops recording the digital data and increments the QUIET TIME timerwhich, as described hereinabove, is a software timer. The program thenproceeds to a function block 1758 that again determines if the voicelevel is above the threshold and, if so, the program proceeds along the"Y" path to a function block 1760 wherein the elapsed time of the QUIETTIME is stored in the VMS. It should be understood that the time thatthe QUIET TIME timer was activated is referenced to the point at whichthe storage of digital data was temporarily terminated. This allows thedata to be reconstituted with all pauses and hesitation, et cetera. Ifthe voice level remains below the threshold, the program goes into alooping function along the "N" path of the decision block 1750 to thebeginning until the threshold has been exceeded. This is essentially asoftware timer that utilizes the finite clock cycles that are requiredto loop from the end of a decision block to the beginning as an amountof elapsed time.

Once the QUIET TIME has been stored, the program returns to the input ofthe function block 1752 to begin storing data again. The program thenproceeds until the message has been completed and the RECORD functionhas been turned off and then follows the "N" path of the decision block1754 to a return block 1762.

Edit

Referring now to FIG. 34, there is shown a subroutine 1764 entitledEDIT. The EDIT feature provides a user with the versatility tomanipulate the content of his message. The EDIT subroutine 1764 is partof the RECORD A MESSAGE function block 1616 of FIG. 28. During recordingof a message, the program proceeds to a decision block 1666 to decidewhether the user has dialed the SFC "1". If this SFC has been dialed,the program proceeds along the "Y" path to a decision block 1768 todecide whether the program is in the RECORD mode. If the program is inthe RECORD mode, the program proceeds along the "Y" path to a STOPRECORD function block 1770 that turns the RECORD function off and stopsstoring digital message data. The program then returns to the input ofthe decision block 1766. If the RECORD function is on after dialing theSFC "1", the program proceeds along the "N" path of the decision block1768 to a function block 1772 wherein the RECORD mode is turned on and amessage is recorded and replaced over the old message at the point thatthe SFC "1" was dialed. This allows a user to record over his oldmessage. For example, if a user desires to change a sentence in themiddle of his message, this feature allows the user to record over onlya portion of the message without having to delete the entire message andstart over. Once the user begins recording, the program returns back tothe input of the decision block 1766. If the user does not desire toeither STOP RECORD or RECORD over his old message, the program proceedsalong the "N" path to a decision block 1774 to decide if the user hasdialed the SFC "2". If the user has dialed this SFC, the programproceeds to a decision block 1776 to decide whether the system is in theRECORD mode. If the system is in the RECORD mode, the program proceedsto a function block 1778 to stop recording and then returns to the inputof the decision block 1776. If the system is not in the RECORD mode, theprogram proceeds along the "N" path to a function block 1780 wherein theRECORD mode is activated and a message may be inserted in the oldmessage at the point that the SFC "2" was dialed. This feature allowsthe user to insert a new message in the middle of an old message. Theprocedure to return to the middle portion of the old message will bedescribed hereinbelow.

If a user does not desire to insert a message, the program proceeds to adecision block 1782 to decide whether the user has dialed the SFC "3".If this SFC is dialed, VMS is instructed to back up ten seconds in themessage and begin replaying the messages indicated by a function block1784 and then the program returns to the input of the decision block1766. If the SPC "3" has not been dialed, the program proceeds along the"N" path to a decision block 1786 to decide if the user has dialed theSFC "33". If this SFC has been dialed, VMS backs up to the start of themessage and replays the message as indicated by a function block 1788.The message will continue to play until the user dials the SFC "1" tobegin recording again. If the SFC "33" is not dialed, the programproceeds along the "N" path to a decision block 1790 that decideswhether the user has dialed the SFC "4". If this SFC has been dialed,VMS is instructed to skip forward ten seconds in the message and beginplaying as indicated by a function block 1792. If this SFC has not beendialed, the program proceeds along the "N" path to a decision block 1794that decides whether the user has dialed the SFC "44". If this SFC hasbeen dialed, VMS is instructed to skp to the end of the message asindicated by a function block 1796. The program then returns to theinput of the decision block 1766 and, if the SFC "44" was not dialed,the program proceeds to a return block 1798.

In operation, the system will either be in a RECORD mode, a HOLDINGmode, or a REPLAY mode. By dialing one of the SFCs in the program ofFIG. 34, a user can manipulate the particular portion of the messagethat he wishes to hear and he can either record over this portion of theold message or insert a new audio message into the old message.

DID/ICH

Referring now to FIG. 35, there is illustrated a flow chart for IncomingCall Handling (ICH) on a Direct Inward Dial Line (DID). ICH is normallyreferred to as the message desk and a normal system refers callers thathave been unable to access the system through a given I.D. to thismessage desk. DID is a special kind of telephone number that ispurchased in blocks of 100 from the telephone company, for example, thenumbers 987-4000 through 5000. The DID number has a characteristic thatwhen anybody in the world dials one of these telephone numbers, theconnection is made between the telephone company and the callinstrument. Call instruments can be either a PBX or the VMS or a similartype system. The last three or four digits that are outpulsed by thetelephone company indicate to the system the number that was dialed. Forexample, if a DID number were dialed to a PBX, the call would bypass theoperator and ring the desired recipient's telephone directly.

Each of the users that is afforded the ICH/DID feature, must own aRECEIVE ONLY (RO) message address that is associated with the user'smessage address and is accessible to anyone dialing the particular DIDthat is associated with the user's RO message address. One applicationof the RO message address would be a "CALL FORWARDING" feature whereinthe user forwarded his telephone number at home or at the office to hisDID/RO number. This would then forward a call that was directed towardhis home or office to his DID number thereby allowing the caller toaccess the messages stored in the RO message address. The caller wouldthen hear the messages in the RO message address previously deposited bythe user/owner and then, if the user/owner desires, be able to deposit aresponsive message in the user/owner's message address.

Referring back to FIG. 27, a function block 1800 labeled DID/ROindicates the initiating block of the subroutine for handling the call.After the program is initiated, the DID digits are received as indicatedby the function block 1802. Upon receipt of the digits, the programflows to a decision block 1804 to decide if the access was successful.If not successful, the program flows along the "N" path to a functionblock 1806 that diverts the caller to the normal ICH procedure whichessentially allows the operator at the message desk to handle theincoming call. This may possibly be due to the fact that the user/ownerforwarded the call to the wrong DID number or there was an error in thesystem. If the access was successful, the program flows along the "Y"path to a decision block 1808 to decide if there are any messages in theRO message address. If the user/owner has not deposited any messages inhis RO message address, the program flows along an "N" patch to afunction block 1810 that plays a CVM such as "This is the VMS answeringservice. The person you called is not in". The program then proceedsback to the main program. If there are messages in the RO messageaddress, the program proceeds along the "Y" path to a function block1812 and the messages in the RO message address are played. Aftermessages are played, the program proceeds to a function block 1814 whichis the same point that the program flows from the function block 1810and a CVM is played to the caller such as "If you wish to leave amessage, please do so at the tone. Hang up at the end of your message".The system then goes into the RECORD mode as indicated by the nextsequential block 1816 to record any messages that might be input by thecaller. The program then proceeds to a decision block 1818 to decidewhether the caller has terminated the call. If the call has not beenterminated, the program is looped back to the input of the decisionblock 1818 to an "N" path and if the call has been disconnected, theprogram flows along a "Y" path to a function block 1820 to turn theRECORD mode off. The program then proceeds to a decision block 1822 todecide if the disconnect occurred less than one second after the recordmode had been turned on. If the disconnect occurred less than onesecond, the program flows along the "Y" path to a function block 1824and the VMS system assumes that no message was received and does notstore any message in the user's normal mailbox. However, if theconnection was maintained more than one second after the record mode wasturned on, the program flows along the "N" path to a function block 1826and the message is stored in the user/owner's message address. Theprogram flows from the output of the function blocks 1824 and 1826 to aRETURN block 1828 to return control of the system to the main program.

RO Deposit

Referring now to FIG. 36, there is illustrated a flow chart for theprocedure to record a message in the user/owner's RO message address.This feature is activated in the main program of FIG. 27 by dialing anSFC having three digits starting with zero. If the user has dialed thesedigits, the program in FIG. 27 proceeds to the routine of FIG. 36defined by a function block 1830 and proceeds to a decision block 1832that decides whether the user that has dialed the particular SFC is theowner of the RO message address. If the user does not own an RO messageaddress, the program proceeds along the "N" path to a function block1834 wherein a triple beep is transmitted to the user to indicate thatthe special command that the user has dialed is invalid. The programthen returns to the main program of FIG. 27 as indicated by a RETURNblock 1836.

If the user is the owner of an RO message address, the program flowsfrom the decision block 1832 along the "Y" path to a decision block 1838to decide if there are any prerecorded messages in the user/owner's ROmessage address.

If there are no prerecorded messages, the program flows along the "N"path to a function block 1840 wherein a CVM is played such as "Your ROmessage address is empty. Dial "9" to insert a new message. Dial * toexit". The program then proceeds to a decision block 1842 that decideswhether the user had dialed "9" or "*". If "*" is dialed, the programproceeds to the RETURN block 1836 to return to the main program of FIG.27. However, if the SFC "0" has been dialed, the program proceeds to afunction block 1844 to play a CVM such as "Dial `1` to record yourmessage. Dial `5` at the end of your message". The user then dials "1"and the RECORD mode is turned on as indicated by a function block 1846and he records his message as indicated by a function block 1848. At theend of his message, the user/owner dials a "5" and the RECORD mode isturned off, as indicated by a function block 1850. The program thenproceeds to a function block 1852 wherein a CVM is played such as "Thenew message has been inserted in your RO message address". The programthen proceeds back to the input of the decision block 1838.

At this point, the program decides whether there are any prerecordedmessages and if so, the program proceeds along the "Y" path to afunction block 1854 that plays a CVM such as "You have [N] RO messages.Dial `8` to hear your messages. Dial `9` to insert a new message. Dial"*" to exit RO message address". The program then proceeds to a decisionblock 1856 to decide which SFC the user has dialed. If the user hasdialed "9", the program proceeds to the input of the function block 1844to record the messages and if the user has dialed "*", the programproceeds to the return block 1836 for return to the main program of FIG.27. However, if the user desires to hear the messages that are stored inhis RO message address, he dials "8" and the program proceeds to afunction block 1858 and the message at the top of the RO message addressqueue is played. At the end of the message, the program proceeds to afunction block 1860 and a CVM instructing the user is played such as"Dial `6` to delete message. Dial `7` to play next message. Dial `*` tostop playing messages". The program then proceeds to a decision block1862 to determine which of the three SFC's the user had dialed. If theuser has dialed "7", the program proceeds to a function block 1864 toincrement the messages and requeue the message at the top of the mailboxto the end of the mailbox queue and then the program proceeds back tothe input of the function block 1858 to play the next message. If theSFC "6" was played, the program proceeds to a function block 1866 todelete the message and then proceeds to a function block 1868 to play aCVM that "The message was deleted from your RO message address". Theprogram then returns to the input of the decision block 1838. If theuser does not desire to delete the message or to hear the remainingmessages in his RO message address, an "*" is dialed and the programreturns to the input of the decision block 1838 for the next step.

Verbal Bulletin Board

Once the user has recorded messages in his RO message address, he caneither use this information stored for connecting to a DID line byforwarding his telephone station to the DID line for access by forwardedcallers. However, the RO message address can also be used for a featureknown as VERBAL BULLETIN BOARD (VBB). This feature allows other users toaccess the RO message address to hear messages therein. This feature isuseful for such people as office administrators who desire to leavegeneral messages relating to the new office procedures, et cetera. Forexample, an office administrator that desires to inform the people in acertain group of a new office procedure would merely deposit a messageregarding the new procedure in his RO message address. Each of the usersin the group would be given his message address and be able to receivethe deposited messages. In this manner, it is no longer necessary tolocate the individuals and verbally tell them of the procedure or todistribute a general memorandum. It should be understood that only auser/owner can deposit messages in an RO message address whereas ageneral user can only receive messages from the RO message address.

RO Access

Referring now to FIG. 37, there is shown a flow chart for the RO messageaddress access which is initiated in the main program of FIG. 27 bydialing an SFC having three digits starting with zero. If this SFC isdialed, the program proceeds to a decision block 1872 to decide whetherthe particular user is allowed access to RO message addresses. This is aC.O.S. that is only available to certain users and not a generalprimitive of owning a message address. If the user is not allowedaccess, the program proceeds along the "N" path to a function block 1874that plays a triple beep informing the user that he has dialed aninvalid command and then returns to the main program as indicated by areturn block 1876.

If the user is allowed access to the RO message address, the programproceeds along the "Y" path to a function block 1878 to play a CVMrequesting the address from the user such as "Dial the address of the ROmessage address". The user then enters the digits in response to theCVM, as indicated by a function block 1880, and then the programproceeds to a decision block 1882 to decide if the dialed address isvalid. First, the decision must be made whether the address is valid andsecond, it must be decided whether an RO message address exists withthis address. If the address is not valid or there is no RO messageaddress with this address, the program proceeds along the "N" path to afunction block 1884 to inform the user that he has dialed an invalidaddress by playing a CVM such as "The address is not a valid one for anRO message address". The program then proceeds to the RETURN block 1876for return to the main program of FIG. 27.

If there are messages in the accessed RO message address, the programthen proceeds from the decision block 1886 along the "Y" path to afunction block 1890 to inform the user of the number of messages thatare contained in the accessed RO message address by playing a CVM suchas "There are [N] bulletin messages. The first one follows". The messageis then played, as indicated by a function block 1982.

RO Reply

After the message has been completed, the program proceeds to a decisionblock 1894 to decide whether the message was the last message in themailbox queue. If so, the program proceeds along the "Y" path to afunction block 1896 informing the user that the bulletin has beencompleted by playing a CVM such as "This completes the bulletinmessage". The program then proceeds to the RETURN block 1876. However,if there are still messages in the mailbox queue, the program proceedsalong the "N" path to a decision block 1898 to decide whether the REPLYprimitive is on. The user/owner has the ability to decide whether hedesires a reply to his messages or not. If so, the REPLY primitive isset during the procedure illustrated in FIG. 36 and the program willproceed along the "Y" path to a function block 1900 to play a CVMrequesting the replay similar to the CVM in the function block 1844 ofFIG. 36. The replay is then recorded in a manner similar to the functionblocks 1846-1850 of FIG. 36, as indicated by a function block 1902 andthen the program proceeds to a function block 1904 wherein the reply isstored in the user/owner's message address for later retrieval. Theprogram then proceeds to a function block 1906 where a CVM "NextMessage" is played. The program then proceeds to the input of thefunction block 1892 to replay another message. If the REPLY primitivewere not off, the program would have proceeded from the decision block1898 along the "N" path to the input of the function block 1906 to playsequential messages.

Send Only Message Address

A feature similar to the RO message address is the SEND ONLY (SO)message address. This is a message address that allows a user/owner tosend messages to other user's message addresses but not to receivemessages or listen to messages. This form of message address is alimited C.O.S. that is useful for people who deliver a great deal ofmessages but prefer not to receive messages from VMS.

Address Information Response

When an address is entered by a user, the system performs a simpleformat check on the address entered to decide whether the address isproper. Once the system decides the validity of the address and thenature of the address, a feature termed ADDRESS INFORMATION RESPONSE(AIR) is utilized by the system. AIR provides two types of enhancedresponse to an entered address. The first type is a set of cannedphrases which provide additional information about the type ofaddresses. Without these features, the system responds to an enteredaddress as follows. "The number you dialed is [spoken digits]." This CVMis replaced with the AIR feature by four different types depending onthe address type as interpreted by the system. The types are users,non-users, networks and group codes. The four CVMs are as follows:

(a) "The user address you dialed is [address]."

(b) "The non-user telephone number you dialed is [digits]."

(c) "The network address you dialed is [digits]."

(d) "The group code you dialed is [digits]."

The second type of AIR applies only to user addresses; it is an addressresponse which includes the spoken name of the user being addressed. Inthis case, the CVM in (a) is changed to "The user address you dialed isfor [user name]." In the present invention, both types of response areused because there is a possibility that some users will not have theirnames recorded in the user data base. This feature is similar to theNAMEPLAY feature described hereinabove with reference to FIG. 29.

Personal Information Message

Another feature that provides the depositor of a voice message withadditional information about the message address he enters is termed thePERSONAL INFORMATION MESSAGE (PIM). The PIM feature enables a user toexercise some control over the address response invoked when he isaddressed by other users. The information provided by PIM is usuallyadded to that provided by AIR. A PIM is a message that is invoked andplayed when the associated user is addressed in a message about to bedeposited. The purpose of the PIM is to provide the message depositor"immediate" information about the address he is using. For example, whena user is setting up a PIM for his own message address, he has severaloptions. First, he may select a prerecorded PIM or record his own"personalized" PIM. Secondly, for prerecorded PIMS, he may select a"short-term" or "long-term" version. The short-term version says thatthe addresse will be " . . . gone for several days . . . " and thelong-term version will be " . . . gone for several weeks . . . ". Third,he may specify that messages addressed to him be diverted to anotheruser's message address, or, alternatively, that his message address isnot allowed as an address for a deposited message. In the later case,the sender hears the PIM following a CVM stating that the address hasbeen deleted. Both the PIM messages and the AIR messages are stored inRO-type message addresses.

Referring now to FIG. 38, there is illustrated a flow chart for the PIMspecial command. The user accesses the special command from the mainprogram in FIG. 27 by dialing a three-digit special command startingwith zero. After the program has been accessed, the main program in FIG.27 proceeds to the program in FIG. 38 initiated at the function block1900 labeled PIM. The program then proceeds to a decision block 1902 todecide if the user is allowed access to the PIM and, if not, a triplebeep is output to the user as indicated by a function block 1904 alongthe "N" path. The program then proceeds to a RETURN block 1906.

If the user is allowed access, the program proceeds from the decisionblock 1903 along the "Y" path to a decision block 1908 that decides ifthere is a prerecorded PIM in the RO message address. If there is noprerecorded PIM in the RO message address, the program proceeds alongthe "N" path to a function block 1910 to inquire whether the user willbe gone for several days or several weeks by outputting a CVM such as"Do you wish to say you will be gone for several days or several weeks:dial `1` for days, or `2` for weeks". The user then responds by dialingeither a "1" or a "2", as indicated by a function block 1912. Theprogram then proceeds to a function block 1914 wherein the VMS entersthe status information into the user's record. The program then proceedsto the input of a function block 1916.

If there was a prerecorded PIM in the RO message address, the programwould proceed from the decision block 1908 along the "Y" path to adecision block 1918 to inquire whether the user desires to use theprerecorded message. Normally, a CVM is played such as "You have aprerecorded PIM. Do you wish to use it? Dial `1` for yes, `2` for no".The user then responds by dialing the appropriate SFC and, if he desiresnot to use the message, the program flows along the "N" path to theinput of the function block 1910 to set the status and, if he desires touse the message, the program flows along the "Y" path to the input ofthe function block 1916.

The function block 1916 plays a CVM to inquire if the message is to bediverted to another message address such as "Do you wish to have yourmessages diverted to another address? Dial `1` for yes, `2` for no". Theprogram then proceeds to a decision block 1920 to decide whether theuser has dialed the correct SFC to divert his messages. If the messagesare to be diverted, the program flows along the "Y" path to a functionblock 1922 that plays the CVM: "Dial the message address". The user theninputs the correct address, as indicated by a function block 1924 andthen the program proceeds to a decision block 1926 to decide if theaddress is valid. If invalid, the program proceeds along the "N" path toa function block 1928 to play a CVM: "The address you entered is not avalid message address". If, however, the address is valid, the programproceeds to a function block 1930 to play a CVM confirming the addresssuch as "Your messages will now be diverted to the following address.[digits for address]". The program then proceeds to a function block1932 to play a completion CVM such as "This completes the set-up of yourPIM" and then the program proceeds to the RETURN block 1906.

If the user had not desired to divert his messages, as indicated in thedecision block 1920, he would dial the appropriate SFC and the programwould proceed along the "N" path to a function block 1934 to play a CVMinquiring whether the user desires no further messages from beingdeposited in his message address such as "Do you want to prevent peoplefrom addressing messages to you? Dial "1" for yes, `2` for no". Then theprogram proceeds to a decision block 1936 to decide whether the user hasdialed the SFC for inhibit. If the user desires to inhibit, he dials theproper SFC and the program proceeds along the "Y" path to a functionblock 1938 to restrict the deposit of voice messages in the user'smessage address. The program then proceeds to a function block 1940 andplays a confirmation CVM such as "From now on, your address is notallowed for voice messages. To remove this restriction later, dial`OXX`". The program then proceeds to the function block 1932 and exitsthe program. If, however, the user does not desire to inhibit futuremessages, the program flows from the decision block 1936 along the "N"path to exit the program. It should be understood that the SFC dialed inthe decision block 1936 has a toggle operation, that is, if the user hasrestricted the user's address previously, the user need only dial theSFC to proceed along the "N" path to remove this restriction.

Self Teach/Help

The RO message addresses described above may also be supplied with"SELF-TEACH" and "HELP" features that make the VMS system easier to usefor a newly indoctrinated user. The SELF-TEACH RO message addressescontain messages describing how to use various system features. Ingeneral, any user can access any of these RO message addresses andlisten to the instructions they contain. The RO message addresses areorganized in an inverted tree-structured manner, that is, the messageaddress at the top of this pyramid contains messages that describe useof the system in general terms, and also provides the message addressesof other RO message addresses that contain more information aboutspecific areas of system operations. There may be several levels ofself-teach RO message addresses. The ones at the lowest levels wouldprobably contain detailed instructions on the use of a single VMSfunction.

The HELP feature consists of a group of individual system enhancementsthat are designed to provide a user additional information, on an "asrequired" basis, about the particular VMS function he is currentlyusing. For example, when VMS is waiting for the user to enter DTMFdigits for some function, it will eventually "time out" and replay thelast CVM prompt and again wait for digits to be entered. It will repeatthis procedure a second time and then abort the function. In addition,the HELP feature is under direct control of the user. If he becomesconfused at some point, he may dial an SFC such as "#", which causes thelast CVM prompt to be replayed immediately. In addition, if a user dialsinvalid digits for some function, a CVM is output to the user to supplythe user more information about what he did wrong. The SELF-TEACH andHELP functions allow a user to more quickly acquaint himself with thesystem and its various operating features.

When VMS initiates a call to an outside telephone station to forcedelivery of a message, VMS can be confronted by either a busy signal,continued ringing or an answer. VMS detects these signals in the Codec96 of FIG. 9 in an answer detect series of filters. The filtersdistinguish between the various tones that result from a busy signalversus a continued ringing. If the phone is busy, VMS then returns thecall within a very short time. However, if VMS detects that the selectedrecipient is not answering his telephone calls, VMS waits a longerperiod of time to return the call. In addition, VMS detects the dialtone that indicates an open line to determine if the call has beenreceived before VMS dials the number.

The hardware for detecting the various signals consists of a frequencypair detection filter for the signal. A dial tone is in the range of a350 Hz and 440 Hz tone signal that must be detected for at least onesecond. A busy signal is comprised of a 620 Hz and 420 Hz tone signalthat alternates on and off for 0.5 second or 0.25 second intervals. The0.5 second interval indicates that the called number is busy, and the0.25 second interval indicates that the trunk is busy. A ring-backsignal consists of a 440 Hz and a 480 Hz tone signal in a repeatingcycle. This repeating cycle is on for one second and off for threeseconds. This signal occurs when the called telephone is ringing but hasnot yet been answered. In order to detect that the call has beenanswered, VMS monitors the line after detecting the ring-back signal todetermine if there is some audio energy above a predefined minimum leveland that no ring-back signal is present. This event indicates that thecalled telephone has been answered.

Message Replay

MESSAGE REPLAY is a feature that gives the non-user who has justlistened to the message the opportunity to hear it again. At thecompletion of playing the message (the first time), VMS would then playa CVM such as the "This is VMS. If you would like to hear this messageagain, please stand by for ten seconds. If you do not wish to hear itagain, please hang up now". VMS would then monitor the line for adisconnect during the ten-second window, and, if it occurs, VMS wouldconsider the message "delivered", and not play it a second time. If nodisconnect occurs during the window, VMS plays the message again.

One important aspect of this feature to be decided by VMS is, if adisconnect occurs during the second playing of the message VMS mustdecide if it should consider the message "delivered". If a disconnectoccurs during the first playing, the message is considered "notdelivered", and another attempt will be made later on a subsequent call.The message should be considered delivered if a disconnect occurs duringthe second playing because the listener will not want to hear the entiremessage twice-only that portion which was not clear to him during thefirst playing.

Non-User Reply

NON-USER REPLY is a feature that provides to the non-user who receives amessage the option to reply to it. This is an option that is under thecontrol of the message originator. The orginator invokes an SFCassociated with the non-user address for the message which triggers theoffering of the reply option to the recipient. At the completion ofplaying the message, the recipient would hear a CVM such as "This isVMS. If you wish to reply to this message, please stand by. If you donot, please hang up now". If VMS does not detect a disconnect within,for example, five seconds, VMS then prompts the non-user to record hisreply with the following CVM: "At the tone, please record your reply.Hang up at the end of your reply". VMS then emits a progress tone andthen records everything said by the non-user until he hangs up. Thisreply message is then sent to the originator of the non-user message.

Interactive Voice Message System

A feature termed INTERACTIVE VOICE MESSAGE SYSTEM (IVM) provides a userwith a feature that "leads" a user through a series of question andanswer sessions (VMS asks the questions and the user provides theanswers). The user's answers are stored in the system to be retrievedlater by a designated user. The applications for this feature would be,for example, an out-of-town sales force that routinely enters a largeamount of sales data such as purchase orders, quantities and customers.With the IVM, it is only necessary for a user to access VMS and respondto a series of questions by either dialing the requisite DTMF digits orapplying the appropriate verbal response.

The questions, or queries, are prerecorded in the VMS system as either aCVM or as a general voice message stored in an RO message address. TheCVMs can be accessed through a computer terminal or the like and it ispossible to have a large quantity of CVMs available to the user thatoriginates the set of questions. He can merely arrange the CVMs toprovide a coherent sequence of questions. If the user so decides, he caninput the questions from a telephone unit in his own voice and arrangethe questions in a manner he desires. In addition, there are provisionsfor a user to place conditional flags on the question such that ananswer to one question allows a calling user to skip through two orthree questions, as will be described hereinbelow.

Referring now to FIG. 39, there is illustrated a flow chart for a user'saccess to the IVM. The user accesses his message address and then dialsa three-digit command beginning with zero to access the IVM subroutine.However, a non-user can also access the IVM by dialing a requisite DIDnumber that can be associated with the particular IVM. After the programis accessed, the program flows to a function block 1944 wherein theaddress of the particular IVM desired. The program then flows to adecision block 1946 that decides whether the address is valid, and, ifnot, the program proceeds to a function block 1948 that outputs a triplebeep to the user indicating an invalid command. However, for a non-user,a CVM would be output such as "The address you have entered is invalid".The program then proceeds to a return block 1950.

If the address is valid, the program proceeds from the decision block1946 along the "Y" path to a function block 1952 that plays anidentifying CVM such as "Hello, this is VMS. You have selected the IVMfor `rotary gear` sales orders". After the identifying CVM is played,the program proceeds to a function block 1954 and plays the message atthe top of the message queue. This message could be something such as"Please enter your name, your sales location and your supervisor". Afterthe message has been played, the program proceeds to a decision block1956 to decide whether DTMF digits or voice response is required. Thisis one of the primitives that the originating user programs in when heselects and/or records the messages.

If the voice response has been selected, the program proceeds to afunction block 1958 wherein the message is recorded. The recordingprocedure is similar to that described above with reference to FIG. 36wherein the user or non-user can select when he begins to record themessage and when he is finished recording the message by dialing anappropriate SFC. In addition, if the caller happens to be a non-user, aCVM can be played instructing the user how to respond. This wouldnormally be done prior to the function block 1952.

After the message has been recorded, the program proceeds to a functionblock 1960 that places the message in an outgoing voice message queue onthe bottom thereof. The outgoing voice message queue is an accumulatingmemory that allows each voice message recorded to be sequentially taggedonto one another. This allows the entire message to be transmitted tothe originating user in a coherent fashion. After the message has beenplaced in the outgoing voice message queue, the program proceeds to adecision block 1962 to determine if there are any messages left in themessage queue.

If the message transmitted to the caller requires a DTMF response, theprogram would proceed from the decision block 1956 to a function block1964 to record the digits. After the digits were recorded, they would beplaced in a DTMF message queue on the bottom thereof. Although notshown, it is possible that the DTMF digits are merely used to advancethe message queue to a different position in the message queue. However,there are some applications that may require the cumulation of digitsfor information purposes. After the messages have been placed in theDTMF message queue, the program proceeds to the input of the decisionblock 1962.

If there are messages remaining in the message queue, the programproceeds along the "N" path from the decision block 1962 to a decisionblock 1968 to determine if the response was DTMF digits. If the responsewas not DTMF digits, the program proceeds along the "N" path to afunction block 1970 that places the previously-played message on thebottom of the message queue and increments the message queue such thatthe next message is on the top of the queue and ready to be played. Theprogram then proceeds to the input of the function block 1954 to playthe next message.

If the response was not DTMF digits, the program would proceed along the"Y" path from the decision block 1968 to the decision block 1972 todetermine if the response was a conditional response. If the responsewas a conditional response, the program would proceed along the "Y" pathto a function block 1974 to increment the message queue to the desiredmessage. If the response was not conditional, the program would proceedalong the "N" path to the input of the function block 1970.

When the last message in the queue has been played, the program proceedsfrom the decision block 1962 along the "Y" path thereof to a functionblock 1978 wherein the message is accrued in the outgoing voice messagequeue or transmitted to the originating user's message address for laterretrieval. In addition, the DTMF digits stored in the DTMF message queuecan also be transmitted to a designated user's message address forretrieval and process at a later time. The program then returns to themain program in FIG. 27.

Referring now to FIG. 40, there is shown an alternate embodiment of themessage delivery of FIG. 15 implementing the feature of NAMEANNOUNCEMENT, AUTO MESSAGE DELETE, and AUTO REPLY. The program isentered through a function block 1973 labeled MESSAGE DELIVERY and thenproceeds to a decision block 1975 to decide whether the message is to bedelivered by depositing it in a user's address or by making an outcallto a telephone station. If VMS is to make an outcall, the programproceeds along the "Y" path to a function block 1976 wherein VMS dialsthe telephone station.

Name Announce

After the telephone station is dialed, the program then proceeds to adecision block 1979 to decide whether the NAME ANNOUNCE primitive is on.The NAME ANNOUNCE feature provides a method for VMS to call a telephonestation and inform the person answering the telephone station who thecall is for. For example, if the NAME ANNOUNCE primitive is on, a CVMwill be played such as "Hello, this is VMS. There is a voice message for[name]. Please dial your I.D." The CVM is indicated by a function block1980. The applications for this feature are in situations where possiblytwo people share the same office and the same phone such that there is apossibility that the person being called will not answer. In initiatingthis feature, the originating user has available to him the names of allusers stored in the user's data base. Once the primitive is on, thesystem automatically retrieves the name of a user/recipient and playsthe CVM with his name inserted therein. It should be understood,however, that this feature can be available for outcalls to non-users byinputting the digits corresponding to the name of the non-user. If theNAME ANNOUNCE primitive has not been turned on by an originating user,upon message delivery, the program will proceed from the decision block1979 along the "N" path to a function block 1982 that plays a standardCVM similar to the CVM in the function block 1980 without the name.After the recipient has entered his I.D., the program flows to the inputof a function block 1984 to process the user I.D. as described abovewith the reference to FIG. 13. This is also the point of the programthat the program flows to for a message delivery that does not utilizean outcall, for example, a user accessing his own voice mailbox formessages.

Auto Message Delete

After the I.D. has been processed, the program proceeds to a functionblock 1986 to replay the message, as described above with reference toFIG. 15. The program then proceeds to a decision block 1988 to decide ifthe AUTO MESSAGE DELETE parameter has been turned on. If the primitivehas been turned on, the program flows along the "Y" path to a functionblock 1990. At this point in the program, the connection is sensed suchthat if the recipient disconnects the telephone, the message willautomatically be deleted or, upon completion of the message, the messagewill be deleted. For example, if an employer wishes to direct a messageto a recipient that is very confidential, the AUTO MESSAGE DELETEfeature allows the employer to restrict the number of times that themessage may be played. In this manner, only the recipient would everhear the message. This is also applicable to messages that may beincriminating to an originating user if these messages were stored forlater replay or redirected to another user. After the message has beendeleted, the program returns to the original program, as indicated by areturn block 1992.

Auto Reply

If the AUTO MESSAGE DELETE feature is not on, the program proceeds fromthe decision block 1988 along the "N" path to a decision block 1994 todecide if the AUTO REPLY feature is on. This feature is initiated by theoriginating user during recording of the message by setting a primitiveat this telephone station. If the AUTO REPLY feature is not on, theprogram flows along the "N" path to the return block 1992 and if thefeature is on, the program flows along the "Y" path to the decisionblock 1996 to decide whether the message is directed to a user or anon-user. if a user is receiving the call, the program proceeds along a"Y" path to a function block 1998 to play a CVM to instruct the user toreply such as "Dial `1` to record your reply and dial `5` when you arethrough. Your message will then automatically be transmitted to theoriginator".

The program then flows to a REPLY block 1999. If the message wasdirected at a non-user, the program flows along the "N" path to afunction block 2000 to play an instructional CVM to the non-user such as"At the tone, please record your reply, five seconds of silence denotesthe end of your reply. Thank you.". The program then proceeds to thefunction block 2002 to turn the RECORD mode on and record the reply. Theprogram then flows to a decision block 2004 to determine whether therehas been five seconds of silence which the VMS interprets as adisconnect. If a disconnect has not occurred, the program flows along an"N" path to return to the input of the decision block 2004. Atdisconnect, the program proceeds along the "Y" path to the input of afunction block 2006 that stores the reply in the originator's messageaddress. After the reply the program proceeds to the RETURN block 1992.

The AUTO REPLY function allows an originating user to instruct VMS toautomatically record a reply without having the recipient initiate theprocedure. In this manner, an originating user does not have to requesta reply in his voice message but, rather, need only activate the properprimitive.

Sequential Group Calling

Referring now to FIG. 41, there is shown a flow chart for a featuretermed SEQUENTIAL GROUP CALLING (SGC). SGC is a feature that allows auser to access a group of people and sequentially deliver a message toeach of the persons therein. VMS then waits a certain period of time forsome event to occur such as a given amount of time elapsing within whicha message recipient must respond to the message. After this event, VMSplays the next call in sequence until the last call has been placed.This will continue until all addresses in the group have been called.The program is initiated by the originating user dialing an SFC thatallows him to deposit a message and access a particular group fortransmission of the message thereto. This is indicated by a functionblock 2008. The program then proceeds to a function block 2010 whereinVMS accesses the group from the user's data base. The program thenproceeds to a function block 2012 and the first address in the group isselected and called by VMS. The program then proceeds to a decisionblock 2014 to determine whether the addressee has answered or not. Ifthere has been no answer, the program proceeds along the "N" path to adecision block 2016 to decide whether the maximum number of attempts hasbeen tried. This maximum number of attempts may be set by theoriginating user and, if not, the maximum number of attempts will bethat allowed by the VMS system in general. If the maximum number ofattempts has not been surpassed, the program returns to the input of thefunction block 2010 along the "N" path. If the maximum number ofattempts have been tried, the program proceeds along the "Y" path.

If the addressee answers, the program proceeds from the decision block2014 along the "Y" path to the function block 2018 and the message isplayed to the addressee. The program then proceeds to a decision block2020 to decide whether a particular event has occurred. As describedabove, this event can be, for example, the passage of a discrete amountof time within which the addressee can reply to the originating user byother means or it can merely be a reply through the VMS system. Inaddition, a discrete event can occur such as the recipient dialing adigit that indicates a positive response, thereby not requiring furthercalls to the remaining members of the group. As described below, thisresults in exiting the program and returning. If the event has notoccurred, the program returns along the "N" path to the input of thedecision block 2020 and waits until the event occurs before proceeding.Although shown as a looping function, normally the program returns tothe main program and waits for the event to occur before returning tothis particular point in the program.

After the event has occurred, the program proceeds along the "Y" pathfrom the decision block 2020 to a decision block 2022 that inquireswhether the last address has been dialed. If the last address has notbeen dialed, the program proceeds along the "N" path to a function block2024 to increment the address. If the last address has been dialed, theprogram proceeds along the "Y" path to the input of a function block2026 to send an acknowledging CVM to the originator to let him know thatall addresses have been dialed. The program then returns through areturn block 2028 to the main program.

If the last address has not been dialed, and the address has beenincremented, the program proceeds to a decision block 2030 to decide ifa maximum count has been exceeded. The maximum count is a softwarecounter that provides an additional degree of versatility in theprogram. For example, if the event in the decision block 2020 requiresonly one person to answer the question with a positive response such asa digit, then the maximum count counter can be incremented such that theprogram will proceed from the decision block 2030 along the "Y" path tothe function block 2026 to send the acknowledging CVM. Another examplewould be an originating user trying to obtain at least three crewmembers for his weekend yacht. Since he only requires a maximum ofpossibly three people, he would only require three positive responses.The input of three positive responses would exceed the maximum count andthe program would then be exited. However, if the maximum is notexceeded, the program proceeds along the "N" path from the decisionblock 2030 back to the input of the function block 2010 to select thenext address in the group. This continues until either the maximumamount has been exceeded or the last address has been dialed.

Status Check

Referring now to FIG. 42, there is illustrated a flow chart of a featuretermed STATUS CHECK. The STATUS CHECK feature allows the user, bydialing an SFC to inquire into the status of a previously-recordedmessage on a specific date. The program is entered at a function block2032 and then the program proceeds to a function block 2034 where theSFC for STATUS CHECK is entered. A CVM is then played such as "Dial thedate of the message in question", as indicated by a function block 2036.The program then proceeds to a function block 2038 wherein the userenters the particular date that he deposited the message. After the dateis entered, the program proceeds to a function block 2040 and VMS playsa CVM requesting the address and then the address is entered, asindicated by a function block 2042. The program then proceeds to adecision block 2044 to decide if there is a record of the call stillstored in VMS. If there is no record, the program proceeds along the "N"path to a function block 2048 where a CVM is played such as "There is norecord of your call. Thank you.". The program then proceeds to a returnblock 2050 to return to the main program.

If there is an existing record of the call, the program proceeds fromthe decision block 2044 along the "Y" path to a decision block 2052 todecide whether the message in question has been delivered. If themessage has been delivered, the program flows along the "Y" path andinforms the user of when the message was picked up. VMS plays a messagesuch as "The voice message you sent to [addressee] at [time] on [date]was picked up at [time] on [date]." The program then proceeds to theRETURN block 2050. If, however, the message was not delivered, then theprogram proceeds along the "N" path to a function block 2056 to informthe user that the message has not been delivered by playing a messagesuch as "The voice message you sent to [addressee] at [time] on [date]has not been picked up." The program then proceeds to the RETURN block2050. The operation of the STATUS CHECK feature provides the user withthe versatility of checking on the status of a message sent to aparticular addressee on a particular date. However, if there were anumber of messages sent to the same date, the messages wouldsequentially be sent back to the user.

DID Answer Delay

Referring now to FIG. 43, there is shown a flow chart for a featuretermed DID ANSWER DELAY. The DID ANSWER DELAY feature allows a user toplace a call on a DID trunk line (described hereinabove) to inquire asto the status of their message address. If there are no messages in themessage address, VMS delays answering by a predetermined time, forexample, four seconds, and the user has the opportunity to disconnectthe call. However, if there are messages in the message address, thephone is immediately answered. An incoming call on the DID trunk line ispreceded by four identifying digits that VMS can use to identify theassociated address. These digits are transmitted from the telephonesystem even though the call has not yet been answered by VMS. In notimmediately answering the call, VMS provides an indication to the userthat there are no voice messages in his mailbox without having to answerthe incoming call.

The program is identified by a function block 2058 DID ANSWER DELAY andthe program then proceeds to a function block 2060 wherein VMS receivesthe DID digits on the incoming DID trunk. After receiving the digits,VMS processes the address by the procedure shown in FIG. 13, asindicated by a function block 2062. After receiving the digits, VMSprocesses the address by the procedure shown in FIG. 13, as indicated bya function block 2062. After the address is processed, the program flowsto a decision block 2064 wherein VMS checks the message address of theaddress for any messages contained therein. If there are no messages,the program proceeds to a function block 2066 along the "N" path anddelays answering the DID call for approximately four seconds. It shouldbe understood that his delay can be longer or shorter depending upon theinitial system design.

If there are messages present in the address, the program flows alongthe "Y" path. After the answer has been delayed for four seconds whenthere are no messages or, alternatively, immediately answered when thereare messages, the program proceeds to the input of a function block 2068wherein VMS provides answer supervision which answers the call and theringing stops. The program then proceeds to a function block 2070labeled NEXT to indicate that the next step would be the normalprocedure for processing a call in VMS.

Fax Transmission

Referring now to FIG. 44, there is shown the flow chart for a featurestermed FAX TRANSMISSION. This feature allows the user to transmit datasuch as drawings and documents through VMS. This subroutine is enteredby dialing an SFC to designate FAX DEPOSIT, as indicated by a functionblock 2072. The program then proceeds to a function block 2074 thatplays an instructional CVM such as "Dial `1` to deposit FAX Group I,dial `2` to deposit FAX Group II, and dial `3` to deposit FAX GroupIII." The user then dials the digit designating the appropriate protocolto be given to the FAX deposit, as indicated by a function block 2076 toplay a CVM requesting the approximate length of the FAX message to bedeposited at functon block 2078. This usually only requires a singledigit. The user then dials the message length digit, as indicated by afunction block 2080 and the program proceeds to a function block 2082 toplay requesting CVM such as "Dial `1` for a 20 Kc sampling rate, dial`2` for a second sampling rate, and dial `3` for a third sampling rate."After this message has been transmitted, the program proceeds to afunction block 2084 wherein the user dials the sampling rate digit. Theaddress is then processed by a function block 2086 that processes theaddress according to the procedure in FIG. 13. After the address isprocessed, an instructional CVM is sent such as "Dial `1` to send yourFAX message, dial `5` when you are through", as indicated by a functionblock 2088. The program then proceeds to a SEND block 2090 wherein theFAX is transmitted. To send a FAX, a user would normally insert histelephone hand unit into a receptacle on a FAX machine and then processthe document therethrough. The FAX machine would encode the graphicmaterial into signals suitable for transmission along a telephone line.Since each FAX machine may possibly have a different sampling rate, thesampling rate digit that was input in function block 2084 allows thesystem to compensate for any variations in sampling rates. After themessage has been completed, the user dials the SFC "5" and the programproceeds to an exit block 2092.

Analog Networking

Referring to FIG. 2, there are two modes of communication between twoseparate VMS systems. The first is via the data link 48 that allowsdigital data to be transferred therebetween and the second is throughthe public telephone network 29. In analog networking, all of theinformation, both route data and message data, are transferred betweensystems through the public telephone network. This procedure isillustrated in a flow chart in FIG. 45 for ANALOG NETWORKING. Forpurposes of explanation, there are assumed to be two systems. A firstsystem "X" transmits the data and a second system "Y" receives the data.

A function block 2094 indicates the steps whereby VMS initiates a callto "Y" over the public telephone network. The program then flows to adecision block 2096 to decide whether an acknowledging touchtone signal(ATT) has been received by "X" and "Y". The ATT indicates to "X" thatthe telephone connection has been made between "X" and "Y". If "X" doesnot receive the ATT, the program proceeds along the "N" path back to theinput of the decision block 2096 until the ATT is received. When the ATTis received, the program flows along the "Y" path to a function block2098 wherein "X" sends the DTMF digits for the user I.D. of the voicemessage to be transportated to "Y". "Y" receives these digits andvalidates the user I.D.

When the user I.D. is validated, "Y" again sends an ATT to "X", asindicated by a function block 2100. The program then proceeds to afunction block 2102 wherein "X" sends the DTMF digits for the addresseeto "Y". "Y" receives these digits and validates the address for theaddressee and again sends an ATT to "X", as indicated by a functionblock 2104. The program then proceeds to a decision block 2106 to decidewhether there are any additional addressees for transmission to "Y". Ifthere are additional addressees, the program proceeds along the "Y" pathto the input of the function block 2102 wherein "X" sends additionalDTMF digits for additional addressees. However, if there are noadditional addressees, the program flows along the "N" path to afunction block 2108 wherein "X" transmits the proper sequence of DTMFdigits to "Y" to turn the RECORD mode of "Y" on. For example, "X" sendsa "0" DTMF digit to "Y", indicating the end of the addressees. "X" thensends a "1" DTMF digit that turns the RECORD mode of "Y" on. The programthen proceeds to a function block 2110 and "X" transmits the spoken textof the voice message.

After the spoken text has been transmitted, "X" turns the RECORD mode of"Y" off by transmitting the proper DTMF digit such as a "5" thatindicates the end of the message. When "Y" receives the "5" digit, theRECORD mode is terminated and "Y" sends an ATT to "X" indicating such,as indicated by a function block 2112. The program then proceeds to adecision block 2114 to decide if there are any additional messages and,if so, the program proceeds along the "Y" path to the input of thefunction block 2098 to send DTMF digits for further users. When all themessages are transmitted, the program flows from the decision blockalong the "N" path thereof to a function block 2116 wherein "X"terminates the call and hangs up. This is normally performed bytransmitting a "*" DTMF digit to "Y" to indicate the end of the call.When "Y" receives the "*", "Y" also hangs up.

Hybrid Networking

A feature termed HYBRID NETWORKING allows VMS systems to communicatewith each other via both the data link 48 of FIG. 2 and the publictelephone network. This provides VMS with a means to transmit some datain the digital mode without having to first convert the digitalinformation to analog format for transmission thereof and to transmitthe audio messages in the analog format. Also, in some instances digitaltransmission for such items as route data occur at a faster rate usingsuch techniques as time sharing, et cetera. A flow chart for both hybridnetworking and digital networking, that is, transmitting everything on adigital data link networking is illustrated in FIG. 46.

The call is initiated by "X" and received by "Y", as indicated by afunction block 2118. The program then proceeds to a decision block 2120wherein "X" waits for "Y" to answer the call. The program proceeds alongthe "N" path back to the input of the decision block 2120 until "Y"answers and then flows along the "Y" path thereof to a decision block2122 to decide whether the message information is to be sent by thepublic telephone network as a spoken voice or is to be sent by thedigital data link as digital information. If the information is to besent by the public telephone network, the program proceeds along the "N"path to a function block 2124. In function block 2124, "X" sends arequesting data packet along the digital data link to "Y" requestingpermission to transmit the message on the public telephone network. Theprogram then proceeds to a function block 2126 wherein "Y" acknowledgesthat it is ready to receive information and sends a data packet alongthe digital data link with a reference number. The reference number isnecessary since all the acknowledging data packets are sent on onedigital data link and the message will be sent on an additional digitaldata link.

If the mode of the message transmission is digital, the program flowsfrom the decision block 2122 along the "Y" path to a function block 2125wherein "X" sends a requesting data pack to "Y" for permission to send adigital message along the digital data link. The program then proceedsto the function block 2126 to receive an acknowledging data package from"Y".

After "Y" has acknowledged that it is ready to receive either digitalinformation along the digital data link or analog information along thepublic telephone network, the program proceeds to a decision block 2128to decide whether it is receiving a digital or an analog transmission ofthe message. If the message is analog along the public telephonenetwork, the program proceeds along the "N" path to a function block2130 wherein "X" turns the record mode of "Y" on. This is usuallyaccomplished by "X" sending the digit "1" to "Y". The program thenproceeds to a function block 2132 and "X" sends the DTMF digitscorresponding to the reference number associated with the message. Afterthe reference number has been transmitted, "X" transmits the spokenvoice message, as indicated by a function block 2134. After the spokenvoice message has been transmitted, "X" turns the record mode of "Y"off, as indicated by the function block 2136.

If the message is to be transmitted along the digital data link, theprogram proceeds from the decision block 2128 along the "Y" path thereofto a function block 2138 wherein the reference number is attached andthe message is sent in digital form along the digital data link. When amessage is received in either the digital or the analog form, theprogram proceeds from either the function block 2136 or the functionblock 2138 to a function block 2140 wherein "X" sends a confirmationrequesting data packet to "Y" to determine if "Y" has received themessage. If "Y" has received the message, "Y" returns a confirmationdata packet to "X", as indicated by a function block 2142. After "X"receives the confirmation data packet, the program proceeds to afunction block 2143 wherein "X" terminates the call and hangs up.

The two forms of networking described with reference to FIG. 46 areeither digital networking or hybrid networking, that is transmissionalong both the digital data link and the public telephone network. Itshould be understood that for digital transmission of message, it is notnecessary for "X" to initiate the original contact with "Y" through thepublic telephone network. The interaction between two VMS systems can beentirely through the digital data link.

Although the preferred embodiment has been disclosed in detail, itshould be understood that various changes, substitutions and alterationscan be made therein without departing from the spirit and scope of theinvention as defined by the appended claims.

What we claim is:
 1. An electronic communication network enablingcommunication between remote locations of a user's network telephonefacility comprising:a plurality of remotely disposed electroniccommunications systems coupled to telephone facilities associated with auser's network telephone facility, each of said electroniccommunications systems having:means for enabling access to said systemsin response to signals transmitted from the user's telephone facility;message storage means for storing digital representations of audiomessages transmitted from the user's telephone facility, the user'stelephone facility coupled to said electronic communication network;route storage means for storing digital representations of route datatransmitted from the user's telephone facility that is coupled to saidelectronic communication network and associated with the audio messagestransmitted from the user's telephone facility, the route dataindicating an intended recipient of the audio messages; means foraccessing stored digital representations of audio messages for aselected recipient in response to said route data; reproducing means forreproducing each of the audio messages from the stored digitalrepresentations accessed by said accessing means to provide reproducedaudio messages; first converting means for accessing and converting thestored digital representations of said route data associated with saidreproduced audio messages generated by said reproducing means to analogtone digit signals such that each of said reproduced audio messages hasassociated therewith said analog tone digit signals representingassociated route data; analog transmitting means for transmitting saidreproduced audio messages and associated tone digit signals generated bysaid reproducing means and said first converting means to another ofsaid communications systems; analog receiving means for receivingreproduced audio messages and associated tone digit signals transmittedto said communications system from another one of said communicationssystems; second converting means for converting tone digit signalsreceived by said analog receiving means to digital representations ofroute data, said audio message storage means storing digitalrepresentations of said received reproduced audio messages andassociated digital representations of route data; means for transmittingreproduced audio messages from said reproducing means to a telephonefacility of a recipient indicated as the intended recipient by theassociated tone digit signals converted by said second converting means;and an analog transmission link for interconnecting said analogtransmitting and receiving means of said communications systems.
 2. Thecommunication network of claim 1 wherein said analog receiving meansincludes means for generating an acknowledging signal in response toreceiving tone digit signals from another one of said communicationssystems, said received tone digit signals generated by said firstconverting means in said another one of said communications systems andrepresenting route data of an intended recipient, said acknowledgingsignal transmitted to said other communications system by said analogtransmitting means.
 3. The communication network of claim 2 wherein saidanalog receiving means includes means for receiving said acknowledgingsignal and sequentially transmitting, in response to said analogreceiving means receiving said acknowledging signal, the reproducedaudio messages associated with said previously transmitted tone digitsignals in response to receiving said acknowledging signal.
 4. Anelectronic communication network enabling communication between remotelocations of a user's network telephone facility comprising;a pluralityof remotely disposed electronic communications systems coupled totelephone facilities associated with a user's network telephonefacility, each of said electronic communications systems having:meansfor enabling access to each of said systems in response to signalstransmitted from the user's telephone facility; message storage meansfor storing digital representations of audio messages transmitted fromthe user's telephone facility, the user's telephone facility coupled tosaid electronic communication network; means for storing digitalrepresentations of route data transmitted from the user's telephonefacility coupled to said electronic communication network and associatedwith the audio messages transmitted from the user's telephone facility,the route data indicating an intended recipient of the audio messages;means for accessing stored digital representations of audio messages fora selected recipient in response to said route data; reproducing meansfor reproducing the audio messages from the stored digitalrepresentations accessed by said accessing means to provide reproducedaudio messages; digital transmitting means for transmitting storeddigital representations of route data from said electroniccommunications system to a selected other one of said communicationssystems; analog transmitting means for transmitting reproduced audiomessages from said reproducing means that are associated with the routedata transmitted by said digital transmitting means from said electroniccommunications system to said selected other communications system;digital receiving means for receiving digital representations of routedata transmitted to said electronic communications system from anotherone of said communications systems; analog receiving means for receivingreproduced audio messages associated with route data received by saiddigital transmitting means from the other one of said communicationssystems, said message storage means storing digital representations ofsaid reproduced audio messages received by said analog receiving meansand said associated digital representations of said route data receivedby said digital receiving means; and means for transmitting reproducedaudio messages from said reproducing means to a telephone facility of arecipient indicated as the selected recipient by the route dataassociated with said reproduced audio messages; a digital data linkinterconnecting all of said electronic communications systems forcarrying digital information from said digital transmitting means in oneof said electronic communications systems to said digital receivingmeans in another of said communications systems and an analogtransmission link for interconnecting said analog transmitting andreceiving means in said communications systems.
 5. The communicationnetwork of claim 4 wherein said digital transmitting means includesmeans for generating an acknowledging signal for transmission to anotherone of said electronic communications systems in response to saiddigital receiving means receiving digital representations of route datafrom said other one of said communications systems over said digitaldata link.
 6. The communication network of claim 5 wherein said digitalreceiving means includes means for receiving said acknowledging signaland sequentially dispersing from said analog transmitting means thereproduced audio messages in response to said acknowledging signal. 7.An electronic communication network enabling communication betweenremote locations of a user's network telephone facility for storing andforwarding audio messages, comprising:a plurality of remotely disposedelectronic communications systems coupled to telephone facilitiesassociated with a user's network telephone facility, each of saidelectronic communications systems having:means responsive to signalsfrom the telephone facility of a user-originator for enabling access toeach of said systems; means for receiving analog data including audiomessage data and associated data from the user-originator's telephonefacility; means for discriminating said analog data into the audiomessage data and associated data, the associated data including routedata indicating an intended recipient of the associated audio messagedata and identifying data indicating the user-originator of theassociated audio message data; means for storing digital representationsof the audio message data discriminated by said means fordiscriminating; means for storing digital representations of saidassociated data discriminated by said discriminating means; means foraccessing stored digital representations of audio messages for aselected recipient in response to said associated data; reproducingmeans for reproducing audio message data from stored digitalrepresentations of the audio message data accessed by said accessingmeans to provide reproduced audio message data, converting means foraccessing and converting digital representations of the associated dataassociated with the reproduced audio message data from said reproducingmeans to analog representations; analog transmitting means fortransmitting analog representations of the associated data andassociated reproduced audio message data generated by said reproducingand converting means from said communications system to a selected otherof said communications systems; analog receiving means for receivinganalog representations of associated data and associated reproducedaudio message data generated by said reproducing and converting means ofanother one of said communications systems and transmitted thereby;means for transmitting reproduced audio message data to a telephonefacility of a recipient indicated as a select recipient by theassociated data associated with the reproduced analog data; and ananalog transmission link connected between said communications systemsfor communicating analog information from said analog transmitting meansin ones of said communications systems to said analog receiving means inothers of said communications systems.
 8. The communication network forstoring and forwarding audio messages of claim 7 wherein said analogreceiving means includes means for generating an acknowledging signal inresponse to receiving analog representations of associated data fromanother one of said communications systems, said acknowledging signaltransmitted to said another communications system by said analogtransmitting means.
 9. An electronic communication network enablingcommunication between remote locations of a user's network telephonefacility for storing and forwarding audio messages, comprising:aplurality of remotely disposed electronic communications systems coupledto telephone facilities associated with a user's network telephonefacility, each of said electronic communications systems having:meansresponsive to signals from the telephone facility of a user-originatorfor enabling access to each of said systems; means for receiving analogdata including audio message data and associated data from theuser-originator's telephone facility; means for discriminating saidanalog data into the audio message data and associated data, theassociated data comprised of route data indicating an intended recipientof the associated audio message data and identifying data indicating auser-originator of the associated audio message data; means for storingdigital representations of the audio message data discriminated by saidmeans for discriminating; means for storing digital representations ofsaid associated data discriminated by said discriminating means; meansfor accessing stored digital representations of audio messages for aselected recipient in response to said associated route data;reproducing means for reproducing the audio message data from storeddigital representations of the audio message data; digital transmittingmeans for transmitting stored digital representations of the associateddata to a selected other one of said communications systems; analogtransmitting means for transmitting reproduced audio message data fromsaid reproducing means and associated with said associated datatransmitted by said transmitting means to said other one of saidcommunications systems; means for synchronizing said digital and analogtransmitting means when both digital representations of the associateddata and reproduced audio message data are transmitted together; digitalreceiving means for receiving digital representations of associated datatransmitted to said communications system by another one of saidcommunications systems; analog receiving means for receiving reproducedaudio message data transmitted by said another communications systemsynchronously with the digital representations of the associated data;and means for transmitting reproduced audio message data to a telephonefacility of a recipient indicated as the selected recipient by theassociated data associated with the reproduced audio message data; adigital data link interconnecting all of said communications systems forcarrying digital information from said digital transmitting means in oneof said communications systems to said digital receiving means inanother one of said communications systems; and an analog transmissionlink interconnecting all of said communications systems for carryinganalog information from said analog receiving means in one of saidcommunications systems to said analog receiving means in another of saidcommunications systems.
 10. The communication network for storing andforwarding audio messages of claim 9 wherein said digital receivingmeans includes means for generating an acknowledging signal in responseto receiving said digital representations of associated data fromanother one of said communications systems, said acknowledging signaltransmitted to said another communications system by said digitaltransmitting means.
 11. A method for enabling communication betweenremote locations of a user's network telephone facility for storing andforwarding audio messages, comprising:accessing one of a plurality ofremotely disposed electronic communications systems coupled to one ofthe telephone facilities of a user's network telephone facility;transmitting audio messages and route data to the accessed one of thecommunications systems from the user's telephone facility through whichaccess was obtained; the accessed one of the communications systemsprocessing the audio messages and route data by:storing digitalrepresentations of the audio messages transmitted from the user'stelephone facility; storing digital representations of the route datatransmitted from the user's telephone facility and associated with theaudio messages to indicate an intended recipient of the audio messages,accessing stored digital representations of the audio messages inresponse to the route data, reproducing the audio messages from theaccessed stored digital representations of the audio messages to providereproduced audio messages, converting the stored digital representationsof the associated route data to tone digit signals, transmitting thetone digit signals and the reproduced audio messages to another one ofthe communications systems, receiving tone digit signals for route dataand reproduced audio messages associated with the route data transmittedby another one of the communications systems, converting the tone digitsignals received from the other of the communications systems to digitalrepresentations of the route data, and transmitting reproduced audiomessages to a telephone facility of a recipient, indicated as theintended recipient by the route data associated with the reproducedaudio messages.
 12. The method for storing and forwarding audio messagesof claim 11 further including after receiving the tone digit signals forroute data and the reproduced audio messages associated with the routedata, generating an acknowledging signal in response to receiving thetone digit signals of the route data that were transmitted by anotherone of the communications systems and transmitting the acknowledgingsignal as tone digit signals to said another of the communicationssystems.
 13. The method for storing and forwarding audio messages ofclaim 12 wherein transmitting the reproduced audio messages and tonedigit signals for the route data further includes receiving from theother of the communications systems to which tone digit signals forroute data were transmitted, tone digit signals representing anacknowledging signal and sequentially transmitting the reproduced audiomessages and tone digit signals for the route data to the other of thecommunications systems in response to receiving the acknowledging tonedigit signals.
 14. A method for enabling communication between remotelocations of a user's network telephone facility and storing andforwarding audio messages, comprising:accessing one of a plurality ofremotely disposed electronic communications systems coupled to thetelephone facilities of a user's network telephone facility;transmitting audio messages and route data to the accessed one of thecommunications systems from the user's telephone facility through whichaccess was obtained; the accessed one of the communications systemsprocessing the audio messages and route data by:storing digitalrepresentations of the audio messages transmitted from the user'stelephone facility, storing digital representations of the route datatransmitted from the user's telephone facility and indicating anintended recipient of the audio messages, accessing stored digitalrepresentations of the audio messages for a selected recipient inresponse to the route data, reproducing the audio messages from theaccessed stored digital representations to provide reproduced audiomessages, providing a digital transmission link between thecommunications systems; digitally transmitting stored digitalrepresentations of route data to a selected one of the communicationssystems over the digital transmission link, providing an analogtransmission link between communications systems; transmittingreproduced audio messages over the analog transmission link to theselected one of the communications systems that is associated with theroute data transmitted over the digital transmission link, digitallyreceiving from the digital transmission link digital representations ofthe route data digitally transmitted by another one of thecommunications systems and which were transmitted to the digitaltransmission link by the other one of the communications systems,receiving reproduced audio messages from the analog transmission linkfrom another one of the communications systems that is associated withthe route data received from the digital data link and which weretransmitted to the analog transmission link by the other one of thecommunications systems, and transmitting reproduced audio messages to atelephone facility of a recipient indicated as the selected recipient bythe associated route data.
 15. The method for enabling communicationbetween remote locations of a user's network telephone facility andstoring and forwarding audio messages of claim 14 further includingafter digitally receiving digital representations of the route data,generating a digital acknowledging signal in response to receiving thedigital representations of the route data that were digitallytransmitted by one of the other communications systems and digitallytransmitting the digital acknowledging signal to the other of thecommunications systems for receipt thereby over the digital transmissionlink.
 16. The method for enabling communication between remote locationsof a user's network telephone facility and storing and forwarding audiomessages of claim 15 wherein transmitting the reproduced audio messagesand digital representations of route data to the other of thecommunications systems further includes digitally receiving the digitalacknowledging signal from the digital transmission link aftertransmission of the digital representations of the route data anddetecting the acknowledging signal and sequentially dispersing thereproduced audio messages associated with the transmitted route data inresponse to receiving the acknowledging signal.